Optical media, read inhibiting agents and methods of making and using same

ABSTRACT

Apparatuses, products, devices and methods of manufacture consistent with the invention include optically readable media with at least one mechanism, chemical, agent, and/or process for limiting the time period that at least a portion of encoded information can be read and/or accessed by an optical beam and/or reader capable of reading the encoded information.

CROSS REFERENCE TO RELATED APPLICATIONS

Priority is hereby claimed under 35 U.S.C. 119(e) from U.S. ProvisionalPatent Application No. 60/627,787 filed Nov. 12, 2004; U.S. ProvisionalPatent Application No. 60/627,638 filed Nov. 12, 2004; U.S. ProvisionalPatent Application No. 60/627,209 filed Nov. 12, 2004; U.S. ProvisionalPatent Application No. 60/627,386 filed Nov. 12, 2004; and U.S.Provisional Patent Application No. 60/711,616 filed Aug. 26, 2005. Thedisclosures of all of the above prior Patent Applications are herebyincorporated by reference as if set forth herein in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to optically readable media.More specifically, apparatuses, products, devices and methods ofmanufacture consistent with the invention are disclosed that includenumerous configurations and/or novel designs for limiting the timeperiod that at least a portion of the encoded information stored on theoptically readable media can be read and/or accessed by an optical beamand/or reader capable of reading information encoded thereon.

BACKGROUND

Optical, magnetic and magneto-optic media are primary sources of highperformance storage technology, which enable high storage capacitycoupled with a reasonable price per megabyte of data stored. The use ofoptical media has become widespread in audio, video, and computer datastorage applications in such formats as compact disc (CD), digitalversatile disc (DVD, including multi-layer structures like DVD-5, DVD-9and multi-sided formats such as DVD-10, and DVD-18), magneto-opticaldisc (MO), and other write-once and re-writable formats such as CD-R,CD-RW, DVD-R, DVD-RW, DVD+RW, DVD-RAM, and the like, hereinaftercollectively “data storage media”. In these formats, data are encodedonto a substrate into a digital data series. In pre-recorded opticalmedia, such as CD, the data are typically pits and grooves embossed onthe surface of a plastic substrate using a method such as injectionmolding, stamping or the like.

In recordable media, the data are encoded by laser, which illuminates anactive data layer that undergoes a phase change, thus producing a seriesof highly reflecting or non-reflecting regions making up the datastream. In these formats, a laser beam first travels through a plasticsubstrate before reaching the data layer. At the data layer, the beam iseither reflected or not, in accordance with the encoded data. The laserlight then travels back through the plastic and into an optical detectorsystem where the data are interpreted.

In some applications, it is desirable to have a limited life for anoptical disc. For example, sample computer programs are provided topotential customers in order to entice them to purchase the software.The programs are intended to be used for a limited period of time.Additionally, music, movies, and other forms of digital entertainmentare currently rented for a limited time period. In each of theseapplications and others, when that time has expired, the disc must bereturned. A need exists for machine-readable optical discs that do notneed to be returned at the end of a rental period. Limited-play discsprovide a solution to this problem.

Several approaches have been proposed to make a limited play opticaldisc based on a layer that changes from a non-interfering state(transparent) where it does not interfere with the reliable reading ofthe information on the optical disc, via an interrogating beam of light,to an interfering state (opaque) where the layer interferes with theoptical reading of the data on the disc. The interference with thereading light source may be due to the layer becoming dark, reflective,highly birefringent, pitting, corroding, bending, changing refractiveproperties or any combination of these. (See for example, U.S. Pat. No.6,011,772 and U.S. Pat. No. 5,815,484 and herein incorporated byreference in their entirety). It should be pointed out that it is notessential in all applications that the interfering layer cover an entiresurface of the disc. It may be desirable to inhibit only the reading ofareas containing critical information content.

SUMMARY OF INVENTION

In one embodiment of the invention, the stimulus triggering the reactionis exposure to atmospheric oxygen. Upon exposure to oxygen, a reactivematerial, which is essentially colorless, is oxidized to form an opaqueor semi-opaque layer. Data storage media with the opaque/semi-opaquelayer can no longer be played in media players. By adjusting the time ittakes to turn opaque, this method can be used to provide limited-playdata storage media having the desired life for the given application.

In one embodiment consistent with the invention a limited life CD,CD-ROM, and/or CD-R optical disc utilizing a corrosive agent and/oragent for degrading the integrity of a reflective layer and/or portionthere of located in a layer and/or region adjacent to the reflectivelayer of the disc is described.

In another embodiment a limited life CD, CD-ROM, and/or CD-R utilizing adye in the optical path of the 780 nm laser is described. The opticaldisc employs two substrates bonded together with a dye adhesive whilethe data layer resides on top of the substrate stack at approximately1.2 mm above the bottom surface of the layered disc.

In yet another embodiment a limited play DVD combined with a CD datalayer or recordable layer is described. In yet still a furtherembodiment a corrosive agent and/or agent for degrading the integrity ofa reflective layer and/or portion thereof located adjacent to one ormore reflective layers of the DVD and/or CD data layer is described.

In a further embodiment a dye material is incorporated in the opticalpath of the reading laser.

In another embodiment a permanent play and/or recordable layer survivesafter the limited play mechanism and/or process is activated and thelimited play layer(s) has ceased to play.

In an embodiment consistent with the invention a limited play DVDincluding recordable and dual layer disc halves using a corrosivematerial and/or an agent for degrading the integrity of at least onereflective layer and/or portion thereof in a layer adjacent to anyreflective layer within the optical disc is disclosed. In an overlappingembodiment a permanent play and/or recordable DVD layer survives afterthe limited play mechanism is activated and the limited play layer(s)has ceased to play.

In another embodiment a limited play DVD including recordable and duallayer disc halves using a dye material to inhibit the ability of thereading laser to read a data layer within the optical disc is disclosed.In an overlapping embodiment a permanent play and/or recordable DVDlayer survives after the limited play mechanism is activated and thelimited play layer(s) has ceased to play.

In a further embodiment consistent with the invention an optical disccombining HD-DVD, HD-DVD-R/RW and/or DVD/DVD-/+R/RW data layers withinone disc where any one or more of the data and/or recordable layers islimited play is disclosed. In an overlapping embodiment, the limitedplay mechanism is a corrosive agent that is adjacent to one or morereflective layer. In a further overlapping embodiment a permanent playand/or recordable DVD layer survives after the limited play mechanism isactivated and the limited play layer(s) has ceased to play. In yetanother overlapping embodiment the read limiting agent is a dye thatinhibits the reading of at least one data layer. In an overlappingembodiment with the dye, a permanent play and/or recordable layersurvives after the limited play mechanism is activated and the limitedplay layer(s) has ceased to play.

In another embodiment an optical medium combining HD-DVD, HD-DVD-/+R/RWand CD, CD-ROM, CD-R, and/or CD-RW data layers within one disc where anyone or more of the data and/or recordable layers is limited play isdisclosed. The limited play mechanism is selected from a corrosivematerial, dye material and/or combinations thereof. If the limited playmechanism is a corrosive material it is located adjacent to at least onereflective layer. In an overlapping embodiment a permanent play and/orrecordable layer survives after the limited play mechanism is activatedand the limited play layer(s) has ceased to play.

In an embodiment consistent with the invention an optical mediumcombining Blu-ray and DVD data and/or recordable layers within one discwhere any one or more of the data and/or recordable layers is limitedplay is disclosed. The limited play mechanism is selected from acorrosive material, dye material and/or combinations thereof. If thelimited play mechanism is a corrosive material it is located adjacent toat least one reflective layer. In an overlapping embodiment a permanentplay and/or recordable layer survives after the limited play mechanismis activated and the limited play layer(s) has ceased to play.

In another embodiment an optical medium combining Blu-ray and HD-DVDdata and/or recordable layers within one disc where any one or more ofthe data and/or recordable layers is limited play is disclosed. Thelimited play mechanism is selected from a corrosive material, dyematerial and/or combinations thereof. If the limited play mechanism is acorrosive material it is located adjacent to at least one reflectivelayer. In an overlapping embodiment a permanent play and/or recordablelayer survives after the limited play mechanism is activated and thelimited play layer(s) has ceased to play.

In another embodiment consistent with the invention limited play Blu-Rayoptical media are disclosed.

In a further embodiment consistent with the invention limited playHD-DVD optical media are disclosed.

In yet a further embodiment consistent with the invention authoringtechniques are employed in conjunction with read inhibiting agent(s).

In another embodiment consistent with the invention the read inhibitingagent is localized to sub-regions of an optical medium.

In a further embodiment consistent with the invention methods andprocesses of making limited play optical media are disclosed.

These and other features and advantages of the present invention will bepresented in more detail in the following detailed description and theaccompanying figures which illustrate by way of example the principlesof the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross section of an optical medium of a limitedlife HD-DVD embodiment consistent with the present invention

FIG. 2 illustrates a cross section of an optical medium of a limitedlife Blu-ray disc embodiment consistent with the present invention.

FIG. 3 illustrates a cross section of an optical medium of a limitedlife Blu-ray disc embodiment consistent with the invention.

FIG. 4 illustrates a cross section of a combined CD and DVD embodimentconsistent with the invention.

FIG. 5 illustrates a cross section of a combined CD and DVD embodimentconsistent with the invention.

FIG. 6 illustrates a cross section of a combined CD and DVD embodimentconsistent with the invention.

FIG. 7 illustrates a cross section of a limited play DVD with a CDrecordable layer embodiment consistent with the invention.

FIG. 8 illustrates a cross section of a DVD and recordable CD embodimentconsistent with the invention.

FIG. 9 illustrates a cross section of a DVD recordable and DVD ROM discembodiment consistent with the invention.

FIG. 10 illustrates a cross section of a DVD recordable and DVD ROM discembodiment consistent with the invention.

FIG. 11 illustrates a cross section of a limited play DVD with apermanent play DVD read from the bottom side embodiment consistent withthe invention.

FIG. 12 illustrates a cross section of a limited play DVD with apermanent play DVD layer embodiment consistent with the invention.

FIG. 13 illustrates a cross section of a limited play HD-DVD dual layertop substrate bonded with a DVD embodiment consistent with theinvention, wherein either or both the HD-DVD layer or the DVD layer arelimited life layers.

FIG. 14 illustrates a cross section of a Blu-ray data layer(s) combinedwith DVD data and/or recordable layers embodiment consistent with theinvention.

FIG. 15 illustrates a cross section of a Blu-ray data layer(s) combinedwith DVD data and/or recordable layers embodiment consistent with theinvention.

FIG. 16 illustrates a cross section of a Blue-ray top data layer (duallayer shown) combined with HD-DVD data layer (dual layer shown) readfrom the bottom embodiment consistent with the invention.

FIG. 17 illustrates a cut away top view with the read inhibiting agentlocalized to a prescribed region consistent with the invention.

FIG. 18 illustrates a cut away top view with the read inhibiting agentlocalized to a prescribed region consistent with the invention.

FIG. 19 illustrates a cut away top view with the read inhibiting agentlocalized to a prescribed region consistent with the invention.

FIG. 20 illustrates a cut away top view with the read inhibiting agentlocalized to a prescribed region consistent with the invention.

FIG. 21 is a graphic illustrating the decay kinetics of a readinhibiting agent in the presence of various film and/or barriermaterials consistent with the present invention.

FIG. 22 is a graphic illustrating the decay kinetics of a readinhibiting agent consistent with the present invention.

FIG. 23 illustrates two disc cross sections illustrating the placementof barrier films in an optical medium in accordance with the presentinvention.

FIG. 24 is a graphic illustrating the optical transmission of the L0substrate with 1% MBI consistent with the present invention.

FIG. 25 is a graphic illustrating the optical density of the adhesive inaccordance with the present invention.

FIG. 26 is a graphic illustrating the optical density of read inhibitagents measured at a preselected wavelength consistent with the presentinvention.

FIG. 27 is a graphic illustrating the absorbance of select readinhibiting agents measured at a preselected wavelength consistent withthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention as illustrated in the accompanying drawings. The samereference numbers may be used throughout the drawings and the followingdescription to refer to the same or like parts. The followingdescription is presented to enable any person skilled in the art to makeand use the inventive body of work. Descriptions of specific embodimentsand applications are provided only as examples, and variousmodifications will be readily apparent to those skilled in the art. Forexample, although many of the examples are described in the context ofcertain data type combinations any single data type may be made limitedplay, it should be understood that embodiments of the present inventioncould be used in any data type combinations even those combinations notexpressly stated, or the like. Similarly, although for the sake ofillustration many of the examples describe a read limiting agent and/ormechanism in the bonding layer, those of ordinary skill in the art willappreciate that the apparatus, devices and products of the presentinvention can be applied to any suitable read limiting agent and/or readinhibiting agent and/or reactive agent anywhere in and/or on the opticalmedium. The general principles described herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the invention. Thus, the present invention is to be accorded thewidest scope, encompassing numerous alternatives, modifications,combinations and equivalents consistent with the principles and featuresdisclosed herein. For purpose of clarity, details relating to technicalmaterial that is known in the fields related to the invention have notbeen described in detail so as not to unnecessarily obscure the presentinvention.

The disclosure frequently makes reference to “substrates,” “dyematerial,” and “corrosive material.” For purposes of clarity, substrateis meant to include any structural member of an optical medium used forsupport and/or to receive a subsequent layer such as for example, a datalayer, reflective layer, bonding layer, buffer layer, lacquer layer, andadditional substrate layer(s). Dye material refers to any material thatprevents the reading beam from reading at least a portion of any dataregion after a predetermined time. Corrosive material refers to anymaterial that degrades the integrity of at least a portion of anyreflective layer and thus prevents the reading beam from reading aportion of any data region after a predetermined time. The disclosureuses reactive agent, read inhibiting agent and read limiting agentinterchangeably to refer to any (either passive or active) mechanism,process, chemical, agent that limits access to encoded informationstored and/or otherwise contained on optical media after a predeterminedtime and/or after a specified event. Further, permanent play is usedinterchangeably to refer to any optical media that is long playing suchthat the encoded information remains accessible after the readinhibiting agent has prevented access to selected encoded information.

The following U.S. patents and patent applications are herebyincorporated by reference in their entirety. U.S. Pat. Nos. 6,641,886;6,838,144; 6,511,728; 6,537,635; 6,839,316; 6,678,239; 6,011,772;6,343,063; 6,434,109; 6,756,103; 6,917,579; and U.S. patent applicationSer. Nos. 10/162,417; 10/016,263; 10/163,473; 10/163,855; 10/163,472;10/651,627; 60/627,209; and 60/627,386.

HD-DVD

The HD-DVD optical media format, proposed and developed by Toshiba andNEC and as described by the DVD Forum, consists of two substrates bondedtogether as in current DVD manufacturing. At least one of the twosubstrates supports encoded information. At least one of the twosubstrates is optically transparent to a reading laser. The HD-DVDformat is similar to current DVD-9 design, as described by the DVD Forum(www.dvdforum.com) and ECMA standard(http://www.ecma-international.org/publications/standards/Ecma-267.htm),in that up to two layers are read by a reading laser from one side ofthe disc. The two data layers of the HD-DVD disc are similar to DVD-9construction but have narrower track pitches with smaller pitstructures. The reading laser of a HD-DVD reading device has awavelength of approximately 405 nm.

The present invention discloses a number of reactive agents that can beused, either alone or in combination, with a HD-DVD disc such that atleast a portion of the encoded information on the HD-DVD disc becomesirreversibly unreadable by the reading laser after a predetermined time.The reactive agents contemplated by the present invention can resideinside and/or on the surface of a HD-DVD disc and/or in the optical pathand/or outside the optical path of the reading laser. FIG. 1 illustratesan HD-DVD limited play embodiment 5 consistent with the invention. FIG.1 shows two substrates 10 and 15, wherein substrate 10 is commonlyreferred to as the L0 side and as referenced through which side theoptical beam reads the encoded information. Substrate 15 is commonlyreferred to as the L1 side. Reflective layers 20 and 25 are separated byat least one intervening layer 30. In the embodiment shown, a readinhibiting agent resides in 30, wherein the reading inhibit agent can beone of a masking compound, such as for example a reactive day and/or adestructive agent, such as a material that corrodes the reflectivity ofat least one reflective layer. The encoded information is readable by anoptical beam(s) 40.

The HD-DVD format uses a similar disc construct to standard DVDs. It istherefore largely compatible with existing manufacturing processes.Manufacturing begins with the injection molding of two 0.6 mm thick discsubstrates. Data can be molded into one or both substrates depending onwhether a single or dual layer disc is being manufactured. Thesubstrates with a data layer are then metallized with either asemi-reflective and/or reflective film and then the two substrates arebonded together. In a dual layer product, the bonding resin is in theoptical path of the laser. For a single layer product, the bonding resinis not normally in the optical path. As described in U.S. patentapplication Ser. Nos. 10/163,473, 10/163,855, 10/163,472, 10/837,826,10/163,821, 10/651,627 and U.S. Pat. No. 6,756,103, all hereafterincorporated by reference in their entirety, the single data layer canbe inverted physically and moved to the L1 substrate creating a singlelayer disc construct that moves the data layer so that the laser mustpass through the bonding resin, therefore putting the bonding layer inthe optical path for a single layer HD-DVD. In this sense, the HD-DVDproduct is similar to DVD Formats disclosed in U.S. patent applicationSer. Nos. 10/163,473, 10/163,855, 10/163,472, 10/837,826, 10/163,821,10/651,627 and U.S. Pat. No. 6,756,103, all hereafter incorporated byreference in their entirety) and DVD-9 product. The differences lie inthe reading laser wavelength as described above. This enables higherdata density through a tighter track pitch and smaller pit sizes,raising storage capacity from 4.7 Gbytes as available on a standardDVD-5 to 15 Gbytes on a single layer HD-DVD.

Blu-Ray

The Blu-ray optical format, proposed and developed by a number ofcompanies and lead by Sony, includes of a single substrate. Thesubstrate of a Blu-ray disc does not need to be optically transparent tothe reading laser because the data is read through a cover layerapproximately 0.1 mm thick. This cover layer is in the optical path ofthe reading laser and is either bonded to the substrate and/or spincoated in one or more layers on the substrate. The reactive agentsand/or read inhibiting agents and/or read limiting agents contemplatedby the present can be used, either alone or in combination, with aBlu-ray disc such that at least a portion of the encoded information onthe Blu-ray disc becomes irreversibly unreadable by the reading laserafter a predetermined time. The reactive agents contemplated by thepresent invention can reside inside and/or on the surface of a Blu-raydisc and/or in the optical path and/or outside the optical path of thereading laser.

In one embodiment consistent with the invention, a reactive dye isintegrated into any of the cover layers that form the optical path ofthe Blu-ray disc and blocks the read laser from reading the encodedinformation after the reactive dye is exposed to a stimulus. FIG. 2illustrates a limited play Blu-ray embodiment 105 consistent with theinvention. FIG. 2 shows a substrate 130 supporting encoded information140 with a reflective layer 120 a bonding layer 125 with a cover layer115 and a hard coat 110. The read inhibiting agent can reside in atleast one of the bonding layer 125, the cover layer 115, and a hard coat110. The encoded information 140 is readable by an optical beam 135. Inthe embodiment shown the reading inhibit agent can be one of a maskingcompound, such as for example a reactive day and/or a destructive agent,such as a material that corrodes the reflectivity of at least onereflective layer.

FIG. 3 illustrates a limited play Blu-ray embodiment 105 consistent withthe invention without a hard coat 110. In the embodiment shown thereading inhibit agent can be one of a masking compound, such as forexample a reactive day and/or a destructive agent, such as a materialthat corrodes the reflectivity of at least one reflective layer andresides in one of the bonding layer 125 and cover layer 115.

Blu-ray discs use a different manufacturing approach than that used forstandard DVDs and HD-DVDs. In Blu-ray discs, the disc substrate isremoved from the optical path, which eliminates issues related to stressinduced birefringence of the molded substrate. A second reason the discsubstrate is removed from the optical path of the reading laser is thatis reduces the disc tilt at the read surface. Disc tilt occurs when thesurface of the disc is not perpendicular to the read laser. A systemwith a higher numerical aperture (NA) lens is more sensitive to disctilt. In Blu-ray, the numerical aperture is increased from 0.6 mm instandard DVD NA, to 0.85 mm. The recording layer and/or data storagelayer of a Blu-ray disc is placed on the surface of a 1.1 mm substrate,protected by a 0.1 mm cover layer. The cover layer is in the opticalpath and is much thinner than the standard DVD L0 layer and HD-DVD 0.6mm substrate. The 0.85 NA enables the use of the high numerical aperturelens at the 405 nm wavelength as the read optics can be closer to thedata layer. Substrate birefringence is eliminated, and surface tiltissues reduced. However, new problems are introduced that require thecover layer to be manufactured according to very stringentspecifications, and surface defects such as scratches or fingerprintsare a much more significant issue than in standard DVD and HD-DVDformats. Hard coatings with the ability to be wiped or cleaned withoutscratching are being developed by the Blu-ray group, which is lead bySony. These hard coatings are also in the optical path and are typicallyspin coated onto the surface of the cover layer.

According to one embodiment consistent with the invention, a limitedplay Blu-ray disc is disclosed. The limited play Blu-ray discincorporates dye absorption technology, i.e., a reactive material and/orread inhibiting agent and/or read limiting agent, in the optical path.The reactive material responds to a stimulus thereby converting from asubstantially transparent state at the 405 nm wavelength to asubstantially opaque state that inhibits the reading of at least aportion of the data layer by the read laser. Dyes selected from thosedisclosed herein can be integrated into the 0.1 mm cover layer and/orsurface coating of the Blu-ray disc. This puts the reactive material inthe optical path of the reading laser. This methodology applies to bothsingle and dual layer Blu-ray discs.

A reactive dye can be incorporated into any or all layers within theoptical path including the bonding layer, 100 micron cover materialand/or hard coat layer. A corrosive agent can be contiguous with thereflective layer and may incorporate the bonding and cover layer, whichcould also serve as a hard surface coat.

CD

In one embodiment consistent with the invention a compact disc(hereafter “CD”) includes a mechanism, chemical, agent and/or processfor limiting the period of time encoded information stored on the CD canbe read and/or accessed. The mechanism, chemical, agent and/or processfor limiting the access time can be applied to CDs that have the encodedinformation encoded during the manufacturing process (i.e., CD-Read OnlyMemory, hereafter “CD-ROM”) and/or encoded information encoded byrecording directly onto the CD (i.e., CD-Recordable and/or CD-Rewritableand the like). Further, the mechanism, chemical, agent and/or processfor limiting the access time is independent of the type and/or kind ofdata and/or information encoded on the CD (i.e., audio, video, data,software, images, text, games, combinations thereof, etc.). CDstandards, put forth by industry groups such as ECMA International,describe the technical and manufacturing aspects of the various CDformats, i.e., CD-Audio, CD-ROM CD-Recordable, CD-Rewritable,CD-Interactive, CD-Video.

The various available CD formats generally adhere to a disc structurebased on a 1.2 mm thick molded substrate with a data layer on the topsurface coated with a reflective layer. The data layer is read from thebottom side of the substrate by a 720 nm laser.

In one embodiment consistent with the invention a limited play opticalCD can be constructed using a corrosive material layer adjacent to thereflective layer. The corrosive agent responds to a stimulus and/ortriggering event, such as for example, exposure to oxygen, which causesthe corrosive agent to react with the reflective layer such that theassociated data layer, or a portion thereof, is no longer readable bythe read laser of the reading device.

In another embodiment consistent with the invention a 1.2 mm thickoptically transparent substrate is constructed with multiple layers, atleast two, of molded substrates. Two 0.6 mm thick substrates are bondedtogether using a reactive dye material to form a 1.2 mm thick substrate.However, it should be noted that two halves and/or substrates of equalthickness are not required, for example, one substrate could be 0.4 mmthick and the other 0.8 mm thick and variations thereof. Moreover, thetotal overall thickness of 1.2 mm is used here, as an exemplaryembodiment and to comply with the specifications set forth by ECMA, ISO,and the DVD Forum so that discs will play in a large percentage of theplayers currently in the homes of consumers. However, as the standardsbodies change the specifications so too the embodiments consistent withthe invention and disclosed herein can be changed and still meet themetes and bounds of the present invention. This statement also appliesfor CD, DVD, High Definition, Blu-ray, and other next generation opticalmedia. The disclosed specific dimensions herein are made to provideexamples of limited play optical media consistent with the invention andto maximize playability in the current install base of current CD andDVD readers and recorders.

FIG. 4 illustrates an embodiment consistent with the invention showing aCD and DVD optical medium 205. The bottom substrate 210, or L0 substrateas it is referred to in a DVD construct, would be a blank disc with nodata structures molded on either surface of the L0 substrate. The secondsubstrate 225, or L1 substrate, is molded with a CD data layer orrecordable structures 220 on the top surface. The surface is then coatedwith a reflective layer or recordable layers 230 to complete the discaccording to its format specifications and as specified by discstandards bodies such as, for example, ECMA and ISO. The reflectivelayer or recordable layers 230 are covered by a protective layer 240.The bottom of the L1 substrate 225 is molded with a DVD data layer orrecordable structures 215. The DVD data layer 215 and the CD data layer220 are readable by optical beams 245 and 250, respectively. Thereactive dye in the bonding layer 235, when exposed to a stimulus and/ortriggering event, such as for example exposure to oxygen, will disablethe ability of the laser to read and/or record data from the disc.

The above embodiments do not require that the limited play mechanism,for example, corrosive agent and/or reactive dye, be an entire layer orbe throughout a single layer and either can be present in limitedregions of the media. For example, the limited play mechanism can belocalized to a region and/or regions that prevent the entire encodedinformation stored on the media from being read by the reading beam.Alternatively, the regions with the localized mechanism will be theregions associated with the limited play mechanism.

CD Hybrids

In yet another embodiment consistent with the invention an optical mediathat includes at least two different types of data structures and/ordata formats and at least one mechanism, chemical, agent and/or processfor limiting access to the data region of either type of data structureand/or data format, all the types of data structures and/or data formatscontained on the optical media, and/or portions thereof is described.This embodiment includes, for example, combinations of at least two datastructures and/or data formats selected from Read Only Memory (ROM),Write Once, Read Many (WORM), Interactive (I), Erasable (E), CD-ROM,CD-WORM, CD-I, DVI, CD-EMO, OD3, ODD, Video Disk, IVD, Blu-ray, HD-DVD,DVD, DVD-R, DVD-Video, DVD-RAM, DVD-Audio, DVD-RAM, DVD-RW, DVD+RW,DVD+R, DVD-Video, SACD, variants of the above, and/or any data structureand/or data format that is readable by an optical beam and/or opticalreading device, including holographic, holographic versatile discs and3-D optical storage devices. In this embodiment, the at least two datastructures and/or data formats may be accessed by the reading beam(s)through the same substrate layer and/or substrate side, i.e., withoutphysically flipping the disc over; each through a unique substrate layerand/or substrate side, i.e., physically flipping the disc over to accessthe data of the other type; or a combination thereof. In an overlappingembodiment consistent with the invention at least one data structureand/or data format may be accessed by the reading beam(s) through thesame substrate layer and/or substrate side, i.e., without physicallyflipping the disc over; each through a unique substrate layer and/orsubstrate side, i.e., physically flipping the disc over to access thedata of the other type; or a combination thereof.

Recordable Format

In still another embodiment consistent with the invention an opticalmedia includes a mechanism for recording information and storing it onthe optical media and a mechanism, chemical, agent and/or process forlimiting the period of time the recorded information is accessible. Thedata format recorded is not limited to CD, DVD, High Definition,Blu-ray, 3-D, and/or holographic data formats and includes anyrecordable data format.

CD/DVD Hybrid

The present invention includes a number of optical media embodimentsthat employ at least one reactive agent and/or material to limit accessto encoded information stored thereon. The disclosed embodiments of thepresent invention can be configured to limit either partial or fullaccess to the encoded information, i.e., only a portion of the encodedinformation will remain permanently accessible or the entire encodedinformation will become inaccessible after a predetermined period. Thedisclosed embodiments include read only and/or recordable configuration.The disc embodiments can employ a reactive agent that masks the encodedinformation, i.e., dye compounds that absorb the wavelength of thereading beam, and/or read inhibiting agent(s) that erodes, corrodes,destroys the integrity of the reflective layer, and/or destroys theintegrity of a substrate material after a predetermined time. Thereactive agent and/or material can be in the optical path of the readingbeam and/or outside the path of the optical reading beam. In addition,limited play characteristics are disclosed in the present invention thatcombine recordable media layers, which allow limited access topre-recorded media, with recordable media layer(s) that retain theability to record permanent data to the optical disc after thepre-recorded media is no longer accessible. These embodiments includethe combinations of a limited play DVD with long playing DVD or CDrecordable layers.

There exists a need for an optical medium that provides both long lifecontent and limited life content because content owners desire aplatform in which to conveniently and inexpensively rent their contentto consumers while minimizing waste. The dual life optical mediumdisclosed in at least one of the embodiments of the present inventionprovides the consumer the necessary incentive to keep the optical mediumlong after the limited life content has expired.

FIG. 5 illustrates an embodiment consistent with the present invention.This embodiment provides an optical medium 305 that contains encodedinformation with two separate life times. The L0 side 310 includesencoded information 320 that is the limited life side. After apredetermined time the encoded information 320 on this side becomesirreversibly inaccessible. The L1 side 315 includes encoded information325 that is the long life side. After the L0 side 310 encodedinformation 320 is not longer accessible the L1 315 encoded information325 will remain accessible. This construct can use either a masking dyeand/or corrosion agent, which resides in the bonding layer 335. If acorrosion agent is employed it eliminates the L0 silver semi-reflectivelayer 330 and thus removes the reflected signal from that layer. Toprevent the thicker silver layer from being affected an alternativereflective material can be substituted for the silver in this layer. Thetop of the L1 side 315 includes encoded information 325, a reflectivelayer 340, and a protective layer 345. The encoded information 320 and325 is read by optical beams 350 and 355, respectively.

These embodiments provide optical media that contains encodedinformation with two separate life times, a limited life and anindefinite life. In these embodiments the encoded information is readfor both DVD and CD from one side. Both metallic and dielectricsemi-reflective layers can be used. Metallic semi-reflective films havean effect on the reading of the 780 nm laser used to read the CD layer.In thinner films, the read signal is still acceptable. Dielectric filmscan be used as the semi-reflective layer. Dielectric films aretransparent at 780 nm and reflective at 650 nm. A combination ofsemi-reflective films may also be used to form a layered semi-reflectivefilm with the corrosive sensitive region of the layer facing the bondingmaterial. Signals for the CD reading laser are improved in thisconstruct but are not always necessary. This construct uses corrosionchemistry with the bonding layer. The corrosion chemistry will eliminatethe L0 silver semi-reflective layer and remove that reflected signalfrom that layer. The thicker full reflective layers bulk properties aredesigned not to be affected by the corrosion chemistry. This can beaccomplished either by the bulk properties of materials (thick film vs.very thin) similar to the semi-reflective film or by changing the fullreflective layer to a different material such as Au, or silver alloythat does not get impacted by the corrosion mechanism. With a dye thatis transparent at the CD 780 nm wavelength but absorptive at the DVDwavelength the DVD will be blocked while the CD will play.

In embodiments consistent with the invention limited play mediaconstructs with modified disc thicknesses are disclosed. In thisembodiment a thin CD is placed back to back with a thin DVD. The CD,DVD, portions of either and/or both, or both disc types include alimited play mechanism, such as for example, a dye in the optical pathand/or corrosion of the reflective layer or portions thereof. Asdescribed above, the CD substrate can be, for example, an audio, ROM,recordable, or rewritable disc while the DVD side can be, for example, aDVD-5, an inverse DVD-5, DVD-9, DVD-Recordable, or DVD-Rewritable. Thesetwo substrates with associated data structures, recording layers, andappropriate reflective layers can be combined together in anycombination.

In yet another embodiment consistent with the invention a CD data layerand a DVD data layer use two substrates bonded together and are readfrom one substrate side.

In still another embodiment consistent with the invention an opticalmedium includes encoded information with two separate life times, alimited life and an indefinite life. In this embodiment the medium isplayed and/or read, for both DVD and CD, from one substrate side. Thereflective layers can be selected from metallic films, dielectricsemi-reflective films, metallic semi-reflective films, dielectric films,and/or combinations thereof.

Metallic semi-reflective films have an effect on the reading of the 780nm laser used to read the CD layer. Dielectric films can be made whichare transparent at 780 nm and reflective at 650 nm. A combination ofsemi-reflective films may also be used to form a layered semi-reflectivefilm. A mechanism for limited the time a reflective layer and/orsemi-reflective layer can be read by a reading beam and/or for limitingthe integrity of a reflective layer and/or semi-reflective layer withthe inclusion of a dye, corrosive material and/or other reading limitingagent in the optical path and/or adjacent to a reflective layer and/orsemi-reflective layer. For example, in one embodiment consistent withthe invention wherein the CD data layer and DVD data layer are read fromone substrate side a corrosive material eliminates the L0semi-reflective layer and removes that reflected signal from that layerafter a predefined period of time.

CD/DVD with Semi-Reflective Layer on DVD-5.

A variant of the above embodiments is to make the DVD portion an inverseDVD-5 as disclosed in U.S. patent applications Ser. Nos. 10/163,473,10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S. Pat.No. 6,756,103, all hereafter incorporated by reference in theirentirety. The L1 side has CD data structures on the top side, and DVDdata structures on the bottom of the same disc half (data structures onboth sides of the top disc half, i.e., L1 side). This embodiment enablesthe use of bonding resins based on either corrosion chemistry as in thetwo examples above or reactive dye chemistry as the bonding layer islocated within the optical path. Both metallic and dielectricsemi-reflective layers can be used. Metallic semi-reflective films dohave an effect on the reading of the 780 nm laser used for the CD layer.In thinner films, the read signal is still acceptable. Dielectric filmssuch as silicon, silicon oxides, or silicon nitrides can be used as thesemi-reflective layer which are transparent at 780 nm and reflective at650 nm. Using reactive dye chemistry, dielectric films do not need to beeroded with a corrosion effect so that they can be optimized for theiroptical properties. This provides signals for the CD layer that meet allspecifications and provide a wider processing window.

Two Discs Bonded Together

Another embodiment consistent with the invention provides an opticalmedium that contains encoded information with two separate life times, alimited life and an indefinite life. In this embodiment, disc thicknessis kept below 1.5 mm which means the two disc halves are manufacturedbelow the lower disc specifications on disc thickness and as specifiedby the DVD Forum and ECMA. For example, a DVD disc half would normallybe manufactured at 0.6 mm and a CD substrate at 1.2 mm. Combining thetwo would create a disc thickness in excess of 1.8 mm when bondedtogether back to back. By reducing the two substrates to just belowminimum thickness specifications, it is possible to achieve a discthickness below 1.5 mm. while still maintaining playability in anestimated 98% of players. Two graphics are shown with the first showinga CD with protective lacquer over the metal layer before bonding, thesecond without the lacquer as it is replaced by the bonding material. Inthis example the limited play mechanism uses the corrosion chemistry toerode the semi-reflective film as described earlier in the text. Thefirst illustration shows a CD with a protective lacquer over the metallayer before bonding, the second illustration shows a CD without thelacquer as it is replaced by the bonding material.

FIG. 6 illustrates another embodiment consistent with the invention. Ahybrid optical medium 405 containing two optically readable formatswherein the format residing on the L0 side 410 is of limited life. Eachformat is readably via optical beams 450 and 440 through its ownsubstrate side. In this illustration the CD format is read through theL1 side 415. A reflective layer 420 resides at the bottom of the L1 side415. A protective layer 425 separates the reflective layer 420 from theL0 side 410. The L0 side 410 contains the DVD format. At the top of theL0 side 410 is a reflective layer 435. An adhesive layer 430 separatesthe L0 side 410 from the L1 side 415. A read inhibiting agent resides inthe adhesive layer 430.

FIG. 7 illustrates another embodiment consistent with the invention. Ahybrid optical medium 505 containing two optically readable formatswherein at least one of the formats is of limited life. Each format isreadably via optical beams 535 and 540 through its own substrate side.In this illustration the CD format is read through the L1 side 530. Areflective layer 525 resides at the bottom of the L1 side 530. The L0side 510 contains the DVD format. At the top of the L0 side 510 is areflective layer 515. An adhesive layer 520 separates the reflectivelayer 525 on the L1 side 530 from the reflective layer 515 on L0 side510. A read inhibiting agent resides in the adhesive layer 520. The readinhibiting agent makes at least one of the two formats unreadable and/orinaccessible after a predefined period of time and/or event.

In another embodiment consistent with the invention, thicker, fullreflective layers are not affected by the corrosive material. This canbe accomplished either by the bulk properties of materials (thick filmvs. very thin) similar to the semi-reflective film or by changing thefull reflective layer to a different material such as Au, or silveralloy that does not get impacted by the corrosion mechanism. Thus,providing an optically readable medium with two time scales ofaccessibility.

In an overlapping embodiment consistent with the invention a bondingresin is in the optical path of the CD read laser. With a dielectricreflective layer on L0, the CD laser is not blocked by this firstreflective layer. The CD laser then reads the L1 data through thebonding resin that includes a reactive dye material that absorbs theread laser after a predetermined period of time. In this embodiment theCD data is of limited duration and/or limited accessibility.Alternatively, the semi-reflective L0 layer is bonded with a materialthat results in corrosion of the L0 reflective layer after a predefinedperiod of time. This configuration degrades the DVD reflective layer andcreates a limited play DVD layer with a CD that is permanent play.

An overlapping embodiment of the above the DVD portion is made using aninverse DVD-5 as disclosed in U.S. patent applications Ser. Nos.10/163,473, 10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627and U.S. Pat. No. 6,756,103, all hereafter incorporated by reference intheir entirety. In this embodiment, the L1 disc has CD data structureson the top side, and DVD data structures on the bottom of the same dischalf (data structures on both sides of the top disc half). Thisembodiment enables the use of bonding resins based on either corrosivematerials as in the examples above or dye materials as the bonding layeris located within the optical path of the reading beam(s). Both metallicand dielectric semi-reflective layers can be used. Metallicsemi-reflective films do have an effect on the reading of the 780 nmlaser used for the CD layer. In thinner films, the read signal is stillacceptable. Dielectric films such as silicon, silicon oxides, or siliconnitrides can be used as the semi-reflective layer, which are transparentat 780 nm and reflective at 650 nm. Using dye materials, dielectricfilms do not need to be eroded with a corrosive material so that theycan be optimized for their optical properties. This provides signals forthe CD layer that meet all ECMA, DVD Forum and ISO specifications andprovide a wider processing window.

In another embodiment consistent with the invention an optical mediumincludes encoded information with two separate discs bonded back toback. In this embodiment, disc thickness is kept approximately in therange of 1.5 mm or lower to keep the overall disc thickness within theranges specified by ECMA and/or ISO. However, as specifications of ECMAand ISO change so to can the disc thickness and be consistent with theinvention. In this embodiment the two disc halves are manufactured belowthe lower disc specifications on disc thickness and as specified by theDVD Forum and ECMA. For example, a standard long playing DVD disc halfis currently manufactured at a thickness of 0.6 mm and a CD substrate at1.2 mm. Combining the two formats into a single disc withoutmodification would create a disc thickness in excess of 1.8 mm whenbonded together back to back. By reducing the two substrates to justbelow minimum thickness specifications, it is possible to achieve a discthickness below 1.5 mm while still maintaining playability in anestimated 98% of players currently on the market. FIG. 5 shows a CD withprotective lacquer over the metal layer before bonding. FIG. 6 shows thediscs bonded without the lacquer layer as it is replaced by the bondingmaterial. In this example the limited play mechanism uses a corrosivematerial to erode the semi-reflective film.

DVD-9 Bonded to a CD

Using a peel technique in the construction of the L1 substrate to make aDVD-9 disc half, a limited play DVD-9 can be bonded back to back with aCD to make a further embodiment consistent with the invention of alimited play DVD combined with a permanent play CD format substrate.FIG. 8 illustrates a dual layer DVD format bonded to a recordable CDformat consistent with the present invention. An L1 side 615 containstwo DVD data layers 660, similar to a DVD-9, with two reflective layers620 and 630 at the top of the L1 side 615 bonded 635 to an L0 side 610.Separating the two DVD data layers is an intervening layer 625, whereina read inhibiting agent resides. The L0 side 610 contains a recordableCD format including a reflective layer 640 and a recordable material645. At least one of the DVD format layers is of limited life. The CDformat and DVD format are read through their respective L0 and L1 sidesvia optical reading beams 650 and 655. The L0 disc half is moldedthinner than ECMA, ISO, DVD Forum specifications to keep total discthickness below 1.5 mm. Since the disc is flipped to be read from eachside, the reflective layers are optimized for each side, CD and DVD.This DVD-9 limited play disc half is then bonded to either a permanentplay or recordable CD, again molded with a thinner substrate.

DVD Formats

These embodiments provide an optical medium that contains encodedinformation with two separate life times. In one embodiment the L0encoded information is the limited life side. After a predetermined timethe encoded information on this side becomes irreversibly inaccessible.The L1 encoded information is the long life side. After the L0 encodedinformation is no longer accessible the L1 encoded information willremain accessible. The corrosion agent eliminates the L0 silverreflective layer and thus removes the reflected signal from that layer.To prevent the L1 reflective layer from being affected by the samemechanism, it can be made thicker and/or an alternative reflectivematerial can be substituted in this layer.

EXAMPLE

DVD-10 discs were made using an L0 reflective layer which was varied inthickness and corresponding reflectivity. It was determined that a greatmajority of consumer players will play a DVD-5 disc half at much lowerreflectivities than DVD ECMA, DVD Forum and/or ISO specifications. Tocreate a limited play optical media, the reflective film was reduced inreflectivity to that of an equivalent layer used in DVD-9 manufacturingof the L0 layer. This reflectivity ranges from 18 to 30%. Discs werealso made at reflectivities increasing until the DVD specification (asdefined by ECMA, ISO and DVD Forum) of 45% was reached. This reflectivelayer is susceptible to corrosion effects. By varying the thickness ofthe reflective layer, one can also effect the play time of the media.Playability was acceptable in our testing with a range of consumerplayers such as the Pioneer DV-563A, JVC XV-N50, and Panasonic DVD S-25.

When the L0 reflective layer was increased until DVD-5 specifications(as defined by ECMA, ISO, and DVD Forum) were met with a minimumreflectivity of 45%, the L0 reflective layer can still be produced withsignificantly less thickness than the L1 layer. This allows the L1 to bemade with the same material but still maintain its reflective propertiesfor permanent play. As mentioned previously, the L1 layer can also bemade with alternate reflective materials such as gold (Au) which wouldnot react to degrade the reflectivity of the layer with the readlimiting mechanism, rendering one side of the disc playable after oneside has failed to play.

DVD-9 with One Recordable Layer

In another embodiment consistent with the present invention a limitedplay disc with a recordable layer is described. A read limiting agent isintegrated within a bonding adhesive, which is used to bond twosubstrates together. The L1 disc half is bonded using an adhesivecontaining a read limiting agent to a L0 substrate with a recordable dyecoated on a grooved surface as specified in recordable formats by thevarious standards bodies. A disc is provided with a limited play L1 datalayer and a recordable L0 layer that will play after the L1 data hasbecome unreadable. Using authoring techniques the entire L0 layer or apart of it can also be defined as a limited play area. Further, thelimited mechanism, does not have to be an entire layer or through outthe disc and instead may be localized to a select region(s), suchlocalization may, depending on the configuration, prevent access to allthe data on a particular layer or selection regions only. The L0 layercould then still be recordable. The disc is authored so that wheninserted into a player, the L1 would be recognized as having beenrecorded and the L0 available for recording.

FIG. 9 illustrates a DVD-9 with a recordable DVD layer consistent withthe invention, wherein at least one layer of the DVD-9 side is of alimited life. An optical medium 705 is formed by bonding two substrates715 and 710 together. The L1 substrate 715 contains two reflectivelayers 720 and 730 separated by an intervening layer 725 at the bottomof the L1 substrate 715. The L0 substrate contains a reflective layer740 and a recording material 745 for recording encoded information. TheL0 substrate 715 and L1 substrate are joined together by a bondingand/or adhesive layer 735. The read inhibiting agent resides in at leastone of the intervening layer 725 and the bonding layer 735.

DVD-R/DVD-5 Limited Play Disc

In yet another embodiment consistent with the invention a disc isconstructed using a DVD-R bonded to a DVD-5. One side plays the DVD-5content, for example, movie or video content. Once flipped over a singlelayer DVD-R is available for recording data. The bonding resin employs amaterial that corrodes the reflective DVD-5 film without attacking thereflective layer of the recordable side.

FIG. 10 illustrates an embodiment consistent with the invention, whereinan optical medium 805 with a recordable layer and limited play layer arecombined. The recordable layer and the limited play layer are readthrough their own unique substrates. As illustrated, the L0 substrate810 contains the recordable layer, wherein the top of the L0 substrate810 includes a reflective layer 830 and a recording material 835. The L0substrate 810 is bonded to the L1 substrate 815 via a bonding and/oradhesive layer 835. The L1 substrate 815 contains the limited play datalayer. The bottom of the L1 substrate 810 includes a reflective layer820. The reading inhibiting agent resides in the bonding layer 835 andallows for the L1 substrate 815 data layer to be of limited life whileallowing the recordable layer to be long playing. The data layers areread by optical beams 840.

FIG. 11 illustrates an embodiment consistent with the invention, whereinan optical medium 905 with a recordable layer and limited play layer arecombined. The recordable layer and the limited play layer are readthrough same substrate side. As illustrated, the L0 substrate 935contains the recordable layer, wherein the top of the L0 substrate 935includes a reflective layer 925 and a recording material 930. The L0substrate 935 is bonded to the L1 substrate 910 via a bonding and/oradhesive layer 920. The L1 substrate 910 contains the limited play datalayer. The bottom of the L1 substrate includes a reflective layer 915.The reading inhibiting agent resides in the bonding layer 920 and allowsfor the L1 substrate 910 data layer to be of limited life while allowingthe recordable layer to be long playing. The data layers are read byoptical beams 940.

DVD 14/18 Constructs

Using existing dye technology, and as disclosed in the above referencedU.S. patents and applications, DVD 14 discs can be manufactured whichcombine a limited play DVD-9 with a permanent play DVD-5 layer. In thisembodiment the limited play techniques disclosed to make DVD-9 productincluding partial dispense and authoring techniques. Once the DVD-9 ismanufactured, the top substrate is mechanically peeled away as in astandard DVD-14 process, and a new top substrate bonded to the disc.This new substrate can be either a permanent play DVD-5, a secondpermanent play peeled DVD-9 half, limited play peeled DVD-9 half, or arecordable DVD-5 half or dual layer recordable DVD disc half. In thisway several combinations of disc halves can be combined usingrecordable, permanent play, or limited play disc halves. For example, alimited play DVD-9 bonded to a permanent play DVD-5 can be read byflipping the disc over. A DVD-9 limited play disc half bonded to asingle layer recordable DVD disc half that must be recorded by flippingthe disc over. In this way disc capacities can be increased, recordablelayers combined with limited play data regions, and permanent play areasextended to entire layers. This provides significant flexibility toaddress many applications of permanent play, limited play, andrecordable applications.

FIG. 12 illustrates an embodiment consistent with the invention. Anoptical medium 1000 includes a DVD-9 format bonded to a DVD-5 format. Atleast one layer or portion thereof can be of limited life. The L1substrate 1010 includes a DVD-5 format with a reflective layer 1015 atthe bottom of the L1 substrate 1010. The L1 substrate 1010 is bonded tothe L0 substrate 1005 via a bonding and/or adhesive layer 1035. The L0substrate 1005 includes a DVD-9 format at its top, with two reflectivelayers 1020 and 1025 separated by an intervening layer 1030. The DVD-9and DVD-5 formats are read through their own substrates by optical beams1040. At least one encoded information layer or a portion thereof is oflimited life.

HD-DVD Formats

It is clear from the discussion and depiction of various constructsabove that many different forms or combinations of optical disc formatscan be combined with limited play technology. This also applies tobringing together various high density disc formats with conventionalDVD formats, or even combining both proposed high density formats,HD-DVD and Blu-ray, on a single disc. The following embodimentsconsistent with the invention combine limited play and/or conventionalHD-DVD and/or Blu-ray data layers with limited play and/or conventionalDVD layers. The Blu-ray and HD-DVD limited play constructs have beendiscussed above. In a further embodiment, all data layers could belimited play or conventional permanent data layers. These constructsprovide a large matrix of possibilities combining formats with andwithout limited play access to either all or selected sections of theencoded information on a data layer.

Limited play optical media can be produced incorporating reactivematerials in the disc substrate, bonding layer, coatings within thestructure of the disc and/or layered on the surface of the disc. A longplaying Digital Versatile Disc (DVD) is normally constructed with thebonding of two 0.6 mm substrates. The current proposed specificationsfor Blu-ray and HD-DVD discs differ in their data layer location anddisc construction. Blu-ray and HD-DVD data layers can be combined in onedisc using reactive materials that can be incorporated into theconstruct of the disc which can eliminate the playability of all or partof the stored data on the disc. Because these discs are stillconstructed from layered substrates, novel constructs can be createdwhich were not anticipated by those who developed the high definitionvideo disc specifications for both Blu-ray and HD-DVD. In particular,the combination of both formats into a single disc with and withoutlimited play data layers is envisioned. Additionally, selected layerscan also include recordable functionality.

HD-DVD and DVD 5/9/Recordable Data Layers

In the HD-DVD specification set forth by the DVD Forum, the productessentially uses two 0.6 mm substrates bonded together much in the sameway as standard DVD. In an embodiment consistent with the invention,standard DVD data layers, both permanent and limited play are combinedtogether with HD-DVD data layers, both permanent and limited play. Forsingle layer HD-DVD and single layer DVD combinations, the two discsubstrates are simply bonded together giving a DVD 5 or single layerDVD-R played or recorded from one side and a single layer HD-DVD orrecordable HD-DVD played or recorded from the other. Either substratecould also have a second data layer added through standard DVD-14/18bonding stripping techniques, or recordable layers added throughstandard dual layer recordable manufacturing processes. FIG. 13 belowillustrates two dual layer substrates bonded together to form an HD-DVDdual layer disc combined with a DVD-9. Any of the data layers can bemade limited play through the addition of reactive materials into thebonding resin, reflective layers, and/or substrates of the disc. Thelimited play capability could limit access to a part of any data layeror all of the data stored on the disc.

FIG. 13 illustrates an embodiment consistent with the present invention.The L1 substrate 1105 includes an HD-DVD data format. The L1 substrate1105 is bonded via a bonding layer and/or adhesive layer 1140 to an L0substrate 1110. The L0 substrate 1110 includes a DVD-9 data format. Thebottom of the L1 substrate 1105 includes two reflective layers 1115 and1120 separated by an intervening layer 1145. The top of the L0 substrate1110 includes two reflective layers 1125 and 1130 separated by anintervening layer 1135. The HD-DVD and DVD-9 formats are read throughtheir own substrates sides via optical beams 1150 and 1155,respectively. A read inhibiting agent limits the life of at least theHD-DVD and DVD-9 format. The read inhibiting agent resides in at leastone of intervening layer 1145, bonding layer 1140, and intervening layer1135.

Blu-Ray and DVD 9/5/Recordable Hybrid Disc

As described above, the Blue-ray disc is constructed with a 1.1 mmsubstrate that is not in the optical path. Therefore it is possible tocreate that substrate using two substrate layers bonded together.Instead of molding substrates with HD-DVD layers, it is also possible touse standard DVD data layers including DVD-5, DVD-9, and single or duallayer recordable data layers within the 1.1 mm substrate of the Blu-raydisc an example of which is shown in FIG. 14. This embodiment combineslimited play capability to a part and/or all of the data stored and/orrecorded onto the disc or any of its data layers.

FIG. 14 illustrates an embodiment consistent with the present invention.The L1 substrate 1205 includes an Blu-ray data format. The L1 substrate1205 is bonded via a bonding layer and/or adhesive layer 1240 to an L0substrate 1210. The L0 substrate 1210 includes a DVD-9 data format. Thetop of the L1 substrate 1205 includes two reflective layers 1215 and1220 separated by an intervening layer 1245. The L1 substrate 1205further includes a bonding layer 1212 and a cover layer 1214. The top ofthe L0 substrate 1210 includes two reflective layers 1225 and 1230separated by an intervening layer 1235. The Blu-ray and DVD-9 formatsare read through their own substrates sides via optical beams 1250 and1255, respectively. A read inhibiting agent limits the life of at leastthe Blu-ray and DVD-9 format and/or a portion thereof. The readinhibiting agent resides in at least one of intervening layer 1245,bonding layer 1240, intervening layer 1235, the bonding layer 1212, andthe cover layer 1214.

To achieve a dual layer DVD-9 using the above construct, a mold, bond,and strip process and/or peel process is typically used to form thesecond layer as in DVD-14/18 manufacturing processes. This could beeliminated if data layers were molded on both sides of the top substrateas shown below in FIG. 15.

FIG. 15 illustrates an embodiment consistent with the present invention.The L1 substrate 1305 includes a Blu-ray data format. The L1 substrate1305 is bonded via a bonding layer and/or adhesive layer 1335 to an L0substrate 1310. The L0 substrate 1310 includes a DVD-9 data format. Thetop of the L1 substrate 1305 includes two reflective layers 1315 and1320 separated by an intervening bonding layer 1335. The L1 substrate1305 further includes a cover layer 1314. The top of the L0 substrate1310 includes two reflective layers 1325 and 1330 separated by anintervening layer 1335. The Blu-ray and DVD-9 formats are read throughtheir own substrates sides via optical beams 1350 and 1355,respectively. A read inhibiting agent limits the life of at least theBlu-ray and DVD-9 format and/or a portion thereof. The read inhibitingagent resides in at least one of bonding layer 1335, intervening layer1315, and the cover layer 1314.

Hybrid HD-DVD and Blu-Ray Disc

In another embodiment consistent with the invention both optical discformats (for example HD-DVD and/or DVD and Blu-Ray) are combined intoone disc as shown in FIG. 16. A Blue-ray substrate is 1.1 mm thick andis not in the optical path of the laser. The data layer is on the topsurface and bonded to a cover layer through a variety of techniquesincluding a spincoated layer, and/or bonding a thin 0.1 mm cover layer,and/or bonding/adhering a film layer to the disc to form the coverlayer. Since the 1.1 mm substrate is not in the optical path of aBlu-ray disc player, that substrate could be two layers bonded togetheras in DVD or HD-DVD manufacturing. The first layer would be 0.6 mm thickwhile the second would be 0.5 mm. The bonding layer could be a nominal55 microns thick for DVD or thinner for the HD-DVD bonding layer. Thesecond disc substrate thickness would be adjusted accordingly dependingon the bonding layer thickness. When bonded the total substratethickness would meet the 1.1 mm Blu-ray substrate specification.

FIG. 16 illustrates an embodiment consistent with the present invention.The L1 substrate 1405 includes a Blu-ray data format. The L1 substrate1405 is bonded via a bonding layer and/or adhesive layer 1440 to an L0substrate 1410. The L0 substrate 1410 includes a HD-DVD data format. Thetop of the L1 substrate 1405 includes two reflective layers 1415 and1420 separated by an intervening layer 1445. The L1 substrate 1405further includes a bonding layer 1412 and a cover layer 1414. The top ofthe L0 substrate 1410 includes two reflective layers 1425 and 1430separated by an intervening layer 1435. The Blu-ray and HD-DVD formatsare read through their own substrates sides via optical beams 1450 and1455, respectively. A read inhibiting agent limits the life of at leastthe Blu-ray and HD-DVD format and/or a portion thereof. The readinhibiting agent resides in at least one of intervening layer 1445,bonding layer 1440, intervening layer 1435, the bonding layer 1412, andthe cover layer 1414.

FIG. 16 above illustrates the hybrid construct of a Blu-ray disccombined with an HD-DVD optical disc. This is a unique and novelconstruction combining data layers that meet the specifications of twodifferent proposed formats within a single optical disc. By using normalbonding and spincoating resins and/or other cover layer constructs foreach format, both data layers would be permanent play data layers. Theincorporation of reactive materials and/or limited play mechanismswithin the bonding layers, and/or cover layer, and or/disc substrate,and/or reflective layers adds limited play capability to part of orentire data layers. In addition, the present invention also contemplatesthe combination of limited play characteristics, permanent playcharacteristics, and/or recordable layers within the construct of asingle disc containing Blu-ray and HD-DVD data layers.

Recordable Limited Life Optical Media

In applications of on-demand recording of digital data including but notlimited to audio or video such as music or movies, it may be desirableto be able to record information onto an optical disc that offerslimited play capability for all or part of the recorded information.This can also be combined with a pre-recorded area or data layer withinthe disc structure.

In yet another embodiment consistent with the invention an opticalmedium is disclosed that can be used at point of distribution toselectively record data, including for example but not limited tosoftware, songs, albums, music videos, feature films, or video segmentsthat the customer desires to purchase. The method of distribution andrecording could be a customer service station at a retail location withthe associated recording device and appropriate packaging system or afully integrated kiosk that is used directly by the consumer to automatethe process and transaction.

An optical disc product to meet these use requirements has been designedcombining a recordable data layer and a limited life mechanism. Thisbasic construct can be combined with any of the preceding embodiment,including a pre-recorded second layer in a limited play DVD-9 format.The use of a second recordable layer is also possible

In one embodiment consistent with the invention the disc constructfollows the standard DVD-9 configuration of a bottom L0 disc half and/orsubstrate bonded to a top L1 disc half and/or substrate. This groovedsubstrate is then coated with a DVD recordable dye and metallized with asemi-reflective film to create the recordable LO data layer within adual layer DVD-9 construct. A read limiting dye is integrated within theadhesive used to bond the L0 and L1 substrates. The L1 substrate ismolded as a pre-recorded data layer as is typical in a DVD-9 L1 datalayer and metallized with a full reflective layer. Optionally, a secondrecordable layer may be used in a dual layer recordable construct. Ineither product configuration, the read limiting dye in the bonding layerlimits access to the entire or selected areas of the second data layerafter a predetermined period of time, limiting access to all or parts ofthe data stored on the optical disc. Interactions between the reflectivelayers and the reactive bonding layer can be prevented with a bufferlayer applied to the reflective layer prior to bonding.

The disc is authored so that when inserted into a player, the L1 wouldbe recognized as having been recorded and the L0 available forrecording. The pre-recorded L1 data layer offers the ability to placedata on the L1 that can serve as a check region or provide software foruse in the player, kiosk, or recorder application. The use of checkregions within the data structure of the disc can be employed to enhancethe capability of a recordable limited play product, defining thelimited play areas and providing access to selected parts of therecorded and pre-recorded information. The L0 layer may also havepre-recorded data in the recordable data area that contains informationfor the player, recording drive, or kiosk station to use as a check discregion, application information, or product configuration information.

The use of partially dispensing the reactive adhesive within the bondinglayer may also be utilized to block the ability of the read laser toread limited areas of the recordable and/or pre-recorded data layers. Inthis way, the media can be configured to selectively allow limited playfeatures to all of, or portions of, the data pre-recorded and/orrecorded within the disc.

While numerous embodiments, including the preferred embodiments, of theinvention have been illustrated and described, it will be appreciatedthat various changes and/or combinations can be made therein withoutdeparting from the spirit and scope of the invention.

Controlled Application of Read Inhibiting Agent(s)

These embodiments provide an optical medium that contains encodedinformation with two separate life times, a limited life and anindefinite life. A DVD-9 with read inhibiting agent on only a portion ofthe disc has been produced. Although this was done on a DVD-9 format,the technique applies to all disc formats and constructs. Authoring isaccomplished so as to either restrict access to data not physicallyblocked, or enabling access to that data. These authoring techniques arean extension of those disclosed in U.S. patent application Ser. No.10/163,473, 10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627and U.S. Pat. No. 6,756,103, all hereafter incorporated by reference intheir entirety. A portion of the optical media without a read inhibitingagent to block the laser and authoring is used to enable access to apart of either layer which would play forever if enabled while otherdata would have at least a major part of it become physically unreadableon all players.

Discs were made with reactive dye bonding material dispensed at theinner diameter (ID), middle, and outer diameter (OD) of the disc with adual dispense system. FIGS. 17 through 20 illustrate distribution of theread inhibiting agent(s) consistent with the present invention. FIG. 17illustrates a read inhibiting agent localized to a wedge section 1510 ofthe outer diameter. The remaining area 1505 can be a bonding agentand/or a secondary read inhibiting agent. FIG. 18 illustrates a readinhibiting agent localized to a larger wedge section 1610 of the outerdiameter. The remaining area 1605 can be a bonding agent and/or asecondary read inhibiting agent. FIG. 19 illustrates a read inhibitingagent localized to a region surrounding the inner diameter 1710. Theremaining area 1705 can be a bonding agent and/or a secondary readinhibiting agent. FIG. 20 illustrates a read inhibiting agent localizedto a region surrounding the inner diameter 1810. The remaining area 1805can be a bonding agent and/or a secondary read inhibiting agent.

If two bonding resins are dispensed within the standard dispense cycle,then a dramatic reduction in the use of costlier reactive dye bondingresin or corrosive chemistry bonding resin can be achieved with minorequipment and/or process modifications.

Benefits of dual dispense process include: active adhesive use reduction(subsequent cost reduction); use reduction allows for dye concentrationincrease (improved chemical stability); and separation ofactive/inactive adhesives: would allow for a secondary chemical failuremechanism to be implemented within the inactive adhesive chemistry, forexample combining reactive dye chemistry with corrosion chemistry ondifferent parts of the disc. The secondary failure mechanism isdisclosed in U.S. patent application Ser. Nos. 10/163,473, 10/163,855,10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No.6,756,103, all hereafter incorporated by reference in their entirety.

A DVD-9 with a reactive agent and/or material (such as a reactive dye)on only a portion of the disc. This results in a portion of the discwithout a reactive agent and thus will not prevent the laser fromreading the encoded information in this region. Authoring is used toenable access to a part of the L1 layer, the portion without thereactive material, which would play forever while the data on a fullside would have at least a major part of it become unreadable on allplayers.

The dual dispense system can also be used to reduce the cost of reactivedye or corrosion materials as mentioned above. For performanceequivalent to a Flexplay DVD-5 or Flexplay DVD-9, the reactive bondresin can be applied at the ID of the disc while a non-reactive bondresin is applied outside of that radius. The two materials are then spuntogether leaving reactive material only at the inner portion of thedisc, which will still cause a boot failure and eliminate access to themenu structure of the disc navigation. The disc will no longer functionafter the pre-determined stimulus activates the inner reactive dye orreactive corrosive material area.

Optical degradation of a limited-play optical medium occurs via exposureof a reactive dye or reactive corrosion agent to a stimulus, such as forexample, oxygen. For example, oxygen transport to the reactive layer islimited by normal incidence bulk diffusion through the polycarbonate“dummy” substrate and any other intervening material layers. Oxygentransport can also occur through disc-edge diffusion at the interfacebetween the reverse-mastered DVD-5 substrate and the dummy substrate orthe edges of the L0 and L1 substrates of a DVD-9. Disc-edge diffusion islimited primarily to the inner and outer diameters of the DVD.Modifications to the oxygen diffusion rates of any intervening layerspresent between the external environment and the oxygen-active layerswill significantly affect the rate of optical degradation of thelimited-play media, thereby providing a mechanism to control the useablelife of the product.

Disc-Edge Diffusion Control

Disc-edge diffusion rates will differ from the normal incidence bulkdiffusion since the reactive layer is either exposed at that narrow areaor is protected by a secondary barrier (e.g., protective acrylatecoating), not typically of the same composition as other components ofthe typical limited-play optical media system. If bulk diffusion ratesare low enough, then disc-edge diffusion will dominate, enabling useabledisc life to be controlled by the preferential optical degradation ateither the inner or outer diameter of the limited-play optical media.Disc-edge diffusion can be controlled through composition and thicknessof the disc-edge barrier. Preferential disc failure through disc-edgediffusion is then achieved by a required playability verification at apredetermined point near either the inner diameter or outer diameter ofthe limited-play optical media. Dominant disc-edge diffusion rates canbe achieved through the use of thin-film diffusion barriers on the dummysubstrate, reduced oxygen diffusion rates through the dummy substrate(e.g., PMMA substrate), or topical diffusion barriers on the surface ofthe dummy substrate (e.g., protective barrier or semi-permeablecoating).

In order to shift away from edge diffusion being the primary factor inthe failure of the disc, a bonding technique has been developed whichkeeps the reactive dye or corrosion chemistry away from the outer edgeof the disc yet still achieves appropriate bonding properties and spacerlayer thickness. This embodiment involves dispensing two separatematerials onto the disc during bonding. Two dispense systems wereimplemented to work in parallel to reduce cycle time. The reactive bondresin is applied at the ID of the disc while a non-reactive or secondaryfailure mechanism enabling bond resin is applied outside of that radius.The two materials are then spun together leaving reactive material onlyat the inner portion of the disc, which will still cause a boot failureand eliminate access to the menu structure of the disc navigation. Thedisc will no longer function after the pre-determined stimulus activatesthe inner reactive dye or reactive corrosive material area. Thelifetime, or viewing window, of the encoded information stored on thedisc is determined by the primary reactive agent in the center of thedisc. In the case of a secondary failure mechanism employed asreferenced in U.S. patent application Ser. Nos. 10/163,473, 10/163,855,10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No.6,756,103, all hereafter incorporated by reference in their entirety,the second material coated outside the ID could contain reactivecorrosive chemistry which would erode the reflective layer after thereactive dye has rendered the disc unreadable. The dual dispense systemcan also be used to reduce the cost of reactive dye or corrosionmaterials by reducing the volume of material used per disc.

Bulk Diffusion Control

If disc-edge diffusion is not dominant in the limited-play DVD system,then diffusion rates of the pre-determined stimulus through the assemblywill be limited primarily by the normal incidence bulk diffusion ratesof the components in the disc assembly. Since diffusion rates throughthe fully reflective layer (e.g., 60 nm aluminum) are negligible, bulkdiffusion through the bottom substrate or L0 substrate coated with asemi-reflective layer and any diffusion barriers applied to thatsubstrate will determine total diffusion rates to the reactive layer.Possible bulk diffusion control mechanisms are described in thefollowing preferred applications:

-   -   1) Diffusion limited substrate composition    -   2) Thin barrier or semi-permeable coating diffusion barrier    -   3) Thin-film diffusion barrier    -   4) Inclusion of anti-oxidants in the substrate, reflective, or        bonding layers    -   5) Inclusion of reduction agents in the reactive dye layer or        reactive corrosive layer        Oxygen Diffusion Limited L0 (DVD-9) or Bottom Dummy        (DVD-Inverse 5) Substrate Composition

Current optical disc manufacturing utilizes optical grade polycarbonate(PC). Oxygen permeability for polycarbonate is approximately100^(cc-mm)/_(m)2_(−d). Decreasing the oxygen permeability of the L0 ordummy substrate, in conjunction with rapid kinetics of reactive dyebonding resin, allows the product decay kinetics to be limitedexclusively by the oxygen permeation rate of the dummy substrate. Discsmade with polymethylmethacrylate (PMMA) for instance significantlyincreased the playtime as the material has a much lower oxygenpermeability compared to normal optical grade polycarbonate. Thematerial property is also very stable regarding permeability so that thestability of the product timing is very good and repeatable. The graphsbelow show readily the extended playtime achievable with changes in thebulk diffusion rate of oxygen as used in an oxygen reactive system withFlexplay reactive dye chemistry:

FIG. 21 illustrates the extended play time using standard PMMA, PC, anda barrier film of aluminum.

FIG. 22 illustrates the decay rates of samples made with PMMA substrateswith two different permeability rates for oxygen showing the tuningcapability of playtime.

Thin Coating Diffusion Barrier

Product decay kinetics control can be achieved by applying a thincoating to the internal or external surface of the L0 or dummysubstrate. The coating has an index of refraction of approximately 1.55and a very low optical absorbance at 650 nm. The coating is appliedthrough a spin-coating process with thickness variation no greater than10% (absolute). The coating thickness and permeability would determinethe product decay. A nominal coating thickness of 10□m should providethe appropriate product decay kinetics for commercially availableoptical hardcoatings. Anti-oxidants and/or reduction agents can also beintegrated within these coatings. FIG. 23 illustrates coatingsconsistent with the invention.

Thin-Film Diffusion Barrier

Bulk oxygen or other pre-determined stimulus diffusion rates to thereactive layer can be reduced through the application of a thin-filmdiffusion barrier. The thin-film diffusion barrier can be applied toeither the internal or external surface of the dummy or L0 substrate. Inessence, the film can be applied to any surface between the environmentand the reactive layer. Diffusion rates through the thin-film diffusionbarrier can be controlled through film composition, thickness, andmorphological structure. A wide variety of materials (metals, metaloxides, etc.) can be used to create the thin-film diffusion barrier,provided that precise deposition techniques such as sputtering orphysical vapor deposition could be used to generate consistent barrierfilms in an optical disc manufacturing environment.

The thin-film diffusion barrier exhibit minimal optical reflection andabsorbance for the wavelength used to read the data recorded within theoptical media. If applied to the external surface of the substrate, itshould also exhibit good mechanical wear and fracture properties.

Example 1

-   -   injection-molded 0.62 mm polycarbonate substrate with        reverse-mastered DVD5* data features; sputter coated with a        fully reflective metallic (aluminum) film: nominally 60 nm thick    -   oxygen-active adhesive material: TipSOC chemistry, rapid        kinetics—nominally 10 hour total deblocked life in limited-play        DVD without diffusion barrier: nominally 50□m thick    -   injection-molded 0.56 mm polycarbonate featureless (mirror)        substrate; sputter coated with 2 nm aluminum-oxide film        (internal surface)    -   acrylate edge-coating to reduce disc-edge diffusion rates,        allowing bulk oxygen diffusion to dominate

The sputter coated thin film of aluminum-oxide provides a significantbarrier to oxygen diffusion. Oxygen permeation rates to theoxygen-active adhesive are limited by grain-boundary diffusion throughthe sputter coated aluminum-oxide thin film. For room-temperaturediffusion processes, grain boundary diffusion rates are several ordersof magnitude faster than bulk diffusion rates. Utilization of ultra-thinmetal-oxide films on a mirror surface minimizes the undesired dummysubstrate reflections and metallic film optical absorbance, allowingdata signal strength from the reverse-mastered substrate to remainwithin an acceptable operation level.

Preferential Optical Degradation

A limited-play DVD utilizing a thin-film diffusion barrier as describedabove could be further tailored so that sharp variations inaluminum-oxide sputtered film thickness would generate preferentialfailure of the limited-play DVD in a “check” region of the DVD program.This preferential failure would prevent content degradation fromoccurring prior to the expiration of the limited-play DVD by causingdisc failure in a “check” region rather than a uniform opticaldegradation that includes the content region of the DVD.

Optical degradation rates will be significantly affected by slightvariations in the thickness of the sputtered thin film diffusionbarrier. Those sharp variations in aluminum-oxide film thickness can beobtained by physically masking the selected “check” region of thelimited-play DVD. One effective means of obtaining the preferential playfailure would be accomplished through using a 48.0 mm diameter centersputtering mask. This masking arrangement would completely cover thelead-in area of the DVD, resulting in a failure to successfully boot ornavigate the play menu prior to any content degradation of the viewedproduct. Another effective method for preferential play failure wouldutilize a check region in the “lead-out” of the limited-play DVD andreduced diameter o.d. sputtering mask that places the mask radiallyinternal to the physical location of the “lead-out” check region.

Example A

-   -   injection-molded 0.62 mm polycarbonate substrate with        reverse-mastered DVD5* data features; sputter coated with a        fully reflective metallic (aluminum) film: nominally 60 nm thick    -   oxygen-active adhesive material: TipSOC chemistry, normal        kinetics—nominally 30 hour total deblocked life in limited-play        DVD without diffusion barrier: nominally 50□m thick    -   injection-molded 0.56 mm polycarbonate featureless (mirror)        substrate; sputter coated with 2 nm aluminum-oxide film        (internal surface), i.d. sputtering mask 48.0 mm diameter

Example B

-   -   injection-molded 0.62 mm polycarbonate substrate with        reverse-mastered DVD5* data features; sputter coated with a        fully reflective metallic (aluminum) film: nominally 60 nm thick    -   oxygen-active adhesive material: TipSOC chemistry, rapid        kinetics—nominally 10 hour total deblocked life in limited-play        DVD without diffusion barrier: nominally 50□m thick    -   injection-molded 0.56 mm polycarbonate featureless (mirror)        substrate; sputter coated with 2 nm aluminum-oxide film        (internal surface)—i.d. sputtering mask at 30.0 mm diameter;        secondary sputter coating, nominal 2 nm aluminum-oxide film—i.d.        sputtering mask at 48.0 mm diameter        Authoring

A limited play optical device becomes unreadable over time (e.g., 1-5days), typically following some stimulus, such as exposure to oxygen. Inembodiments of the present invention, The optical device is designed andauthored, or the reading device is programmed, so that the readingdevice to read from a desired region before playing the rest of thecontent on the disc. If information in that region, referred to here asa “check region,” is unreadable, the player will not read from the restof the medium. This system is preferably used with discs that becomeunplayable over time (e.g., in a few days) and is particularly usefulwhere the disc becomes unplayable not all at once but progressively.

The check region is preferably provided in a place where the disc wouldbe expected to become unreadable earlier than most other regions. In thecase of a disc that becomes unreadable over time in the presence ofoxygen, the check region could be at an outer peripheral region. Bychecking the playability of the check region and preventing play if thecheck region is unplayable, the situation of having a partially playablebut deteriorated disc is reduced or avoided. Authoring tools can be usedto cause the check region to be read first, and to cause the reader togenerate an error indicating that the disc is not readable. The readercould be programmed or modified to accomplish this result.

DVD authoring describes the process of creating a DVD video that can beplayed on a DVD player. DVD authoring software must conform to thespecifications set by the DVD Forum group in 1995, and as they evolvefrom time to time to preserve maximum player compatability. Thespecifications are complicated due to the number of companies that wereinvolved in creating them.

Examples of authoring vendors include Apple, Authoringware, Avid,Blossom Technologies, Canopus, Daikin, DreamCom, DV Studio, Futuretel,Houpert Digital Audio, InnovaCom, Intec America, InterVideo, MargiSystems, Matrox, Mediachance, Microboards, Minerva, Minnetonka AudioSoftware, MTC, NEC, Nero, Optibase, Panasonic, Pegasys, Pinnacle,Philips, Pioneer, PixelTools, Q-Comm, Roxio, SADie, Sonic Solutions,Sony Media Software, Sony Professional, Spruce Technologies, Ulead,Visible Light, and Vitech.

Corrosion

In the embodiments of the present invention, optical media is disclosedwherein access to encoded information therein is limited by affectingthe reflectivity of the semi-reflective and/or reflective layers. Inoptical disc media, the reading laser must be reflected back to the readoptics by these reflective layers so that the encoded information storedthereon can be read. Depending on the layer (i.e., single or dual layerdiscs), the reflective material can be sensitive to the wavelength ofthe read laser. The reflective layer can be any metal, combination ofmetals, reflective dielectric film or films (e.g. SiN) or otherreflective material capable of undergoing the required/desired redoxreaction in the presence of oxygen or after the addition of oxygen tothe system. Metallic reflective layers are much less sensitive to laserwavelength while dielectric films can be created which will betransparent at one wavelength while reflecting another. Both types ofreflective layers can be used in optical media. Within the DVD, HD-DVD,and Blu-ray specifications, reflective layers are typically metallic andpotentially subject to corrosion effects. The chemistry and examplesdescribed in the following section are independent of the read laserwavelength and will provide limited-play capabilities via corrosivedestruction in all optical media formats that utilize metallicreflective layers including DVD, HD-DVD, and Blu-Ray.

The reflective layer can be irreversibly altered by oxidation ordestruction of its reflective properties as a result of pitting,corroding, dissolution, etc., or any combination of these. (See U.S.Pat. Nos. 6,434,109, 6,343,063, 6,011,772, 6,641,886, 6,511,728,6,537,635, 6,678,239, 6,756,103, and 5,815,484 and U.S. PatentApplication Nos. 20030152019, 20030123379, 20030123302, 20030213710,20030129408, 20030112737, Ser. Nos. 10/649,504, 10/162,417, 10/163,473,10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627 and20010046204, hereinafter incorporated by reference in their entirety.).It should be pointed out that it is not essential in all applicationsthat the interfering layer covers an entire surface of the disc. It maybe only necessary to inhibit the reading of areas containing criticalinformation content. Various patents instruct that this reactive layercan be applied to the disc at several locations (on the surface of thedisc, on the surface of the reflecting layer itself, in the adhesive,etc. see patents above) using a variety of techniques and can undergothe change from non-interfering to interfering in response to variousstimuli including oxygen see U.S. Pat. Nos. 6,434,109, 6,343,063,6,011,772, 6,641,886, 6,511,728, 6,537,635, 6,678,239, 6,756,103, and5,815,484 and U.S. Patent Application Nos. 20030152019, 20030123379,20030123302, 20030213710, 20030129408, 20030112737, Ser. Nos.10/649,504, 10/162,417, 10/163,473, 10/163,855, 10/163,472, 10/837,826,10/163,821, 10/651,627 and 20010046204, hereinafter incorporated byreference in their entirety.

It was desirable to determine the extent of corrosion of thesemi-reflective layer (L0) of optical media resulting from its exposureto various corrosive agents under a variety of physical and chemicalconditions. Simulated DVD-9 discs were made using bonding agents thatcontained the potentially corrosive materials of the present invention,a polycarbonate blank with a typical silver L0 layer, and apolycarbonate blank with no highly reflective layer (L1). These discswere made in this way so that visible-NIR light transmission of the thinL0 silver layer could be monitored; an increase in optical transmissionindicates the dissolution or removal of the reflective metallic silverlayer as a result of the action of the corrosive agents of the presentinvention. Using this spectrophotometric method it was possible toevaluate the efficacy of corrosive agent variables such as corrosiveagent concentration, reflective silver layer (L0) thickness, adhesivecomposition, atmospheric composition, and the addition of kineticregulators.

Bonding agent formulations which contained 1.0% of the test corrosiveagent were used to prepare the simulated DVD-9 discs described above.The particular bonding agent of this test contained greater than 50% byweight of polyethylene oxide moieties in order to provide some polarcharacter to the reaction matrix. Initial readings of the transmissionof the discs were made on a Cary 50 Scan UV-Visible Spectrophotometerand the discs were then stored in the dark at ambient temperature andhumidity. Readings were made periodically over a 7 day period. FIG. 24represents typical transmission spectra of the L0 layer of the simulatedDVD-9 disc that contained MBI in the bonding agent over this 7 day timeperiod; the increasing % T over time is indicative of a loss of silvermetal layer as a result of corrosion.

From the sulfur containing agents shown below, MBI was selected as themost reactive corrosive agent with current bonding agent formulations.Results of these tests are shown in TABLE 1. The less reactive materialsin this test may prove more effective with changes in the bonding agentchemistry. TABLE I Comparison of the increase in light transmission at1000 nm that occurred after 48 hours of ambient air storage of thesimulated DVD-9 discs that contained the various sulfur containingagents in the bonding agent layer.

% Increase in Transmission @ 1000 nm after 48 Corrosive Agent hours inair MBI 2-Mercaptobenzimidazole (CAS 583-39-1) 8 MMBI2-Mercapto-5-methylbenzimidazole 5.6 (CAS 27231-36-3) DPTUN,N-Diphenylthiourea (CAS 102-08-9) 4.8 MNBI2-Nitro-5-methylbenzimidazole 3.4 (CAS 6325-91-3) MBT2-Mercaptobenzothiazole (CAS 149-30-4) 0.8 DBTU N,N-Dibutylthiourea (CAS109-46-6) 0.7 MBO 2-Mercaptobenzoxazole (CAS 2382-96-9) 0

Another quick screening method for the ability of various agents tocorrode the L0 silver layer was used. Drops of SR495 containing 1% to 2%of the test agents were placed on the metal surface of a standardsemi-reflective L0 silver coated substrate and observed over a 24-72hour period while exposed to air. Changes in the appearance of thesilver layer as well as its adhesion to the polycarbonate substrate werenoted over time and compared to appropriate controls. The followingtable describes the corrosion effects that were observed. Test AdditiveEffect on Silver Reflectivity Control (no additive) no effect, fullyreflective silver remains after 72 hrs. MBI blackish at 1-2 hrs, silverdissolved in ˜4 hrs Dithiothreitol dissolved silver in <24 hrsMercaptothiazoline blackish discoloration 3-Mercapto-1,2-propanediolblackish discoloration Cysteine methyl ester HCl black/bronzediscoloration with clearing in 72 hrs Dimethylaminoethanethiol HClblackish discoloration with some clearing of silver

These compounds are also known as “bleaching accelerators” in thephotographic industry (U.S. Pat. Nos. 3,893,858; 4,865,956, hereinincorporated by reference in their entirety) where they are used inconjunction with oxidizing agents to accelerate the oxidation of silverduring the development of color photographic images. Therefore, theabove type compounds were also tested in combination with the followingbenzoquinone oxidants and their reduced precursors to evaluate theirability to corrode the L0 silver layer. The “limited play” format maythus be further controlled in its timing characteristics by utilizationof the inactive hydroquinone precurser in the manufacture of the DVDdisc; subsequent exposure to air will generate the active benzoquinoneoxidant at the proper time. Combinations of the following compounds withthe above thiols appeared to improve/accelerate their ability to oxidizethe silver layer in the test described above: 2,5-Di-t-amylhydroquinone(Lowinox AH25); 2,5-t-butylhydroquinone; 2,5-t-Butylbenzoquinone;2,5-Dichlorohydroquinone; 2,5-Dichlorobenzoquinone;2,3-Dicyanohydroquinone; and 2,3-Dicyanobenzoquinone. Also tested wereimidazole, benzimidazole, benzotriazole, mercaptobenzimidazole, and1-phenyltetrazole-5-thiol, as these were also described as bleachaccelerators. Combinations of imidazole and the hydroquinones appearedparticularly effective in dissolving the silver layer.

In the embodiments of the present invention, a corrosive agent is usedto inhibit the reading of the encoded optical data layer via oxygeninitiated corrosion of the reflective layer. The corrosion results inthe destruction of the reflective layer to such an extent that the filmno longer has sufficient reflectivity to support the optical reading ofthe reflective film by a conventional player. The corrosion reaction ofthe present embodiment involves the utilization of sulfur compounds,and, in particular thioureas, the leading example of which is2-mercaptobenzimidazole (2-MBI, Sigma-Aldrich Catalog # M320-5,Milwaukee, Wis. 53201) which has the ability, in the presence of oxygen,to corrode reflective thin silver layers as are typically found withinoptical media. It has been demonstrated that stable high quality opticalmedia can be manufactured containing 2-MBI in the bonding agent withstandard replicating equipment when the completed discs are stored in asuitable oxygen free atmosphere and that said discs become unplayablewithin a predetermined time period after being exposed to ambient air.

Example 1. DVD-9 discs were made with silver L0 and L1 layers, both on“low gas permeation” polycarbonate utilizing bonding agents that had thefollowing compositions; Formulation A was a control that contained no2-MBI, Formulation B contained 0.25% 2-MBI, and Formulation C contained0.5% 2-MBI. Common to all three formulations were the followingmaterials: SR415 and SR495 (monomers, Sartomer Company, Inc.; Exton, Pa.19341), and Irgacure 819 (photoinitiator, Ciba Specialty Chemicals,Tarrytown, N.Y. 10591). Weight, grams Component A B C SR415 201.0 201.0201.0 SR495 201.0 201.0 201.0 IC819 7.70 7.70 7.70 2-MBI 1.025 2.05

Immediately after manufacture, the DVD-9 discs were sealed in plasticpackages containing oxygen scavenger material as described in previouspatent applications (see U.S. patent application Ser. No. 10/162,417,hereafter incorporated by reference in its entirety). To demonstrate theoxygen dependence of the limited play mechanism of the presentinvention, playability comparisons were made between discs that had beenopened and stored in air and those that remained in the oxygen freepackages and played as soon as they were opened; storage temperatureswere room temperature and 60° C. The discs were periodically tested forplayability on a typical DVD player (Samsung DVD P-231). The discs wereconsidered to have failed when the player would not recognize that disc(boot failure). Results are shown in the following table. Days Storageuntil Boot Failure 60° C. RT (20° C.) Formulation air cryovac aircryovac A: 0% MBI >60 >30 >90 >90 B: 0.25% MBI <3 >14 20 >77 C: 0.50%MBI <3 >14 17 >77

It will be noted that the above table provides evidence of the oxygendependence of the limited play corrosion based system and the dependenceof the corrosion rate on the concentration of MBI.

Example 2. Further work has shown that playtime failure is stronglydependent on the thickness of the L0 silver layer. DVD-9 discs were madewith standard DVD grade polycarbonate using a bonding agent that wasmade up by blending 486 grams of SR415 (Sartomer Company, Inc.), 486grams of SR495 (Sartomer), 18.6 grams of Irgacure 819 (Ciba SpecialtyChemicals), and 10.0 grams of 2-mercaptobenzimidazole (2-MBI,Sigma-Aldrich). The thickness of the L0 silver layer of this set ofdiscs was varied and characterized by reflectivity values from 16% R14Hto 24% R14H. As described in Example 1, the discs were manufactured,stored in oxygen-free bags which were opened at the start of playtimetesting, and tested on a typical DVD player. Playtime failure wasdetermined as the number of elapsed hours from the time the discs wereremoved from the oxygen free bags to the time that the discs could notbe recognized by the DVD player. These results are shown in thefollowing table as two values: Last Hour Played (the last hour that thedisc was successfully played)/First Hour of Boot Failure (the first hourthat the disc could not be played). Storage Hours in Air to Boot FailureLast Hour Played/First Hour of Boot Failure 16% R14H 18% R14H 21% R14H24% R14H 20/35 28/47 52/69 96/336The table shows increasingly longer playtimes in the discs with the morereflective, and thus thicker, L0 silver layers.

The increased ease of silver oxidation in the present invention may beattributed to several features of the combination of the thin silver L0coating and the chemical properties of mercaptans like MBI. The bindingof MBI to the silver surface lowers the redox potential of the silvermaking it easier to undergo air oxidation (Tarasankai Pal, CurrentScience, 83, 627-628 (2002)). It also complexes with the generatedoxidized form of silver, helping to maintain the low oxidation potentialin the face of increasing silver ion concentrations (G. I. P. Levenson,“The Theory of the Photographic Process 4^(th) Edition” chapter 15, T.H. James (ed.), Macmillan publishing Co. Inc., New York, 1977; U.S. Pat.No. 5,641,616 and references therein). In addition, heterogeneity in thethin silver L0 layer can lead to areas favoring increased air oxidation(Pal (2002), Wei Ping Cai et. al., J. Appl. Phys., 83, 1705-1710(1998)). The fact that MBI is reportedly used as an antioxidant in themanufacture of industrial rubber (Zenovia Moldovan, Acta Chim. Slov.,49, 909-916 (2002); U.S. Pat. No. 5,666,994, herein incorporated byreference in its entirety) and as an agent to inhibit corrosion of brassand copper (Assouli et al., Corrosion, 60, 604-612 (2004); Robert B.Faltermeier, Studies in Conservation, 44, 121-128 (1999)) supports ourcontention that the observed corrosion effects in our system are notexpected. In addition, MBI has been used as a corrosion inhibiting agentin radiation curable compositions for optical media (U.S. PatentApplication US 2003/0008950 A1, herein incorporated by reference in itsentirety).

The chemical nature of the monomers and additives that are utilized toformulate the bonding agents of the present invention has an importanteffect on the rate of corrosion of the silver layers. Since it is wellknown that rates of redox reactions in polymer media are stronglydependent on the amount of humidity (water) present, the incorporationof water attracting materials and monomers has been found to be ofadvantage. In particular, the utilization of highly ethoxylated monomershas been found to be particularly advantageous. Examples of thesemonomers include CD9038, bisphenolA diacrylate with 30 units of ethyleneoxide; SR415, trimethyolpropane triacrylate with 20 units of ethyleneoxide; SR610, polyethylene glycol 600 diacrylate; and SR344,polyethylene glycol 400 diacrylate (all available from Sartomer Co.).The cured bonding agents containing MBI typically show increasedcorrosion rates, and thereby shorter limited life playtimes, as theconcentration of ethylene oxide moieties is increased from about 5% byweight up to as high as 80% by weight. The preferred level of ethyleneoxide is above 50% by weight. Additives and monomers that contain otherhydrophilizing groups such as hydroxyl, carboxyl, amides, and amines,and various salts may also utilized both alone and in combination withothers. This listing of hydrophilic moieties is not all inclusive andthose skilled in the art may combine a wide variety of hydrophilicfunctionalities, both polymerizable and non-polymerizable, in order tobalance the corrosion rates with the physical robustness of the limitedplay disc.

Another means of controlling the rate and timing of the corrosionreactions is via the addition of reducing agents. These reducing agentswill, after the optical media is exposed to the atmosphere,preferentially react with the initial influx of oxygen until thereducing agent is consumed, at which point the corrosive agent willbecome active in causing destruction of the reflective properties of themetal layer(s). As an alternative explanation, the reducing agent maycause the active corrosive materials to exist in a lower oxidation statewhich is inert to the reflective metal; after the reducing agent isconsumed, the corrosive agent precursor is converted (oxidized) by airto form the corrosive material. The following example utilizestetrachlorohydroquinone (TCHQ) as a non-corrosive precursor in thebonding agent; after exposure to oxygen, TCHQ is oxidized to thebenzoquinone form which has a higher oxidation potential and thus ismore able to oxidize the reflective silver layers. As an alternativeproposed corrosion mechanism, it is also possible that the benzoquinoneform releases chloride ion which is known to cause corrosion of metallayers in optical media.

Example 3. The use of reducing agents has been successfully used tocontrol the oxidation of silver layers by tetrachlorohydroquinone (TCHQ)in the bonding agent of the optical media. DVD-9 discs were made withFormulations D and E which contained TCHQ alone and TCHQ in combinationwith ascorbic acid. Weight, grams Formulation# Component D E SR415 97.8897.63 SR495 97.88 97.63 IC819 3.74 3.74 TCHQ 0.50 0.50 Ascorbic Acid0.50

The discs were equilibrated in the absence of air as previouslydescribed for one week and then opened and stored in air in a wetchamber to accelerate the corrosion reactions. The discs were tested forplayability as described in Example 1; the increased playtime offormulation E is a result of the presence of ascorbic acid: Last Day ofFirst Day of Formulation Play Boot Failure D 2 3 E 6 10

Similar effects of increased playtime have been observed using ascorbylpalmitate and stannous octanoate as reducing agents. Many other reducingagents as described in U.S. patent application Ser. Nos. 10/163,473,10/163,855, 10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S. Pat.No. 6,756,103, all hereafter incorporated by reference in theirentirety, may be applicable here in varying formulations as may beformulated by those skilled in the art.

Stannous octanoate has been found to be the preferred reducing agent forthe control of the corrosion based limited-play timing mechanisms of thepresent invention, but has the unfortunate ability to occasionally causepremature polymerization of typical monomer mixtures. To prevent this,the addition of increased levels of polymerization inhibitors, such ashydroquinones, has allowed the formulation of corrosive bonding agentsthat exhibit stable viscosities for up to several days in the presenceof the stannous salt. The preferred hydroquinone is2,5-di-tert-pentylhydroquinone (Lowinox AH250, Great Lakes ChemicalCorporation, West Lafayette, Ind.) used at a 0.10% to 1.0% by weightconcentration and preferably between 0.2% to 0.5% by weightconcentration. Another compound that has shown success in controllingviscosity of monomer formulations in the presence of stannous salts isphenothiazine (CAS 92-84-2; Sigma-Aldrich Cat. No. P14831) when used atsimilar levels as Lowinox AH25 above.

An additional problem that arises in the use of stannous octanoate withthe hydrophilic monomer mixtures that are preferred in thetime-controlled corrosive bonding agent systems described above is theformation of hazy mixtures. Presumably, this is a result of poorsolubility of the stannous salt in the predominantly polyethylene oxidecontaining mixture. We have found that clear solutions are formed whenstannous octanoate is first dissolved in tripropylene glycol (TPG, CAS24800-44-0; Sigma-Aldrich Cat. No. 187593). Since TPG is not expected tocopolymerize within the cured bonding agents and may exhibit undesirablesyneresis, tests were done on peeled discs at 60 C in order toaccentuate the observation of any possible exudation of liquid; nosyneresis or exudation was observed under these conditions when TPG wasincorporated at levels up to 10% by weight of the cured bonding agent.

Example 4 demonstrates that the incorporation of TPG also has abeneficial effect on maintaining a high corrosion rate of silver metallayers in DVD-9 discs even when stored in air under low humidityconditions. Stannous octanoate was pre-dissolved in varying amounts ofTPG and combined with Stock Solution F to make Bonding Agents G, H, andI. The resulting bonding agents contained 2.7%-3% MBI, 0.25% stannousoctanoate and 0%, 5%, and 10% by weight TPG. Stock Solution F Weight, %by Component grams Weight CD9038 540 54.00% SR238 175 17.50% SR495 142.514.25% SR440 100 10.00% Lowinox AH25 2.5 0.25% IC819 10 1.00% MBI 303.00%

Formulation # Weight, grams Component G H I Stock Solution F 249.38236.88 224.38 TPG 0 12.5 25 Stannous Octanoate 0.625 0.625 0.625

DVD-9 discs were made as described above in Examples 1 and 2; L0thickness was quantified by a 24% R14H reflectivity and standard gradepolycarbonate was used. The discs were stored in oxygen free bags for 4days, then opened and stored in air at room temperature under the threedifferent humidity conditions, dry (one gallon polyethylene containerwith desiccant packages), ambient (open to room air), and wet (onegallon polyethylene container with wet paper towels on the bottom). Theresults shown below as Average Playtime were determined as the midpointbetween the last day that the disc was observed to play and the firstday that the disc would not boot on the Samsung DVD Player. AveragePlaytime, Days G H I 0% TPG 5% TPG 10% TPG Air Storage Dry (<10% RH)17.5 12.5 9 Condition ambient 5 3.5 3.5 100% RH 2.5 2.5 2.5

These results show that increasing the TPG level has the benefit ofreducing the variation in limited playtime between high and low humidityconditions.

Dye Compounds as Reactive Material and/or Read Inhibiting Agents

The reading laser wavelength for HD-DVD and Blu-ray discs has changedfrom standard CD (780 nm) and standard DVD (650 nm) optical media to 405nm. In order to block the blue laser wavelength, the present inventiondiscloses a group of reactive materials that exhibit absorptiveproperties at the 405 nm frequency. In addition to dyes that can simplyabsorb the read laser wavelength, dyes that can be both reduced to thecolorless leuco-form as well as be re-oxidized by oxygen to the coloredform or change absorption characteristics when exposed to a triggeringstimulus can also be used. It is also desirable, but not necessary, thatthe reduced free dye (e.g., leuco dye) responds to a mechanism forcontrolling the rate of oxidation (e.g., the re-oxidation of leucomethylene blue (i.e., leuco dye) can be controlled by a reducing agentsuch as stannous octanoate. (US 2004/0137188 A1 herein incorporated byreference in its entirety).

One embodiment consistent with the present invention comprises the useof a chemically blocked and/or modified and/or protected reactive dye(s)in the reactive layer. These compounds will de-block within apredetermined time period after the disc is manufactured or packaged,and typically before the disc is used by the consumer. This is desirablewhen the stimulus that triggers the reaction that causes the disc tobecome unplayable (e.g., atmospheric oxygen) can trigger this reactionduring the manufacturing of the disc, and thus measures need to be takenso that the reactive compound is not activated during the manufacturingof the disc. For example, in the case of oxygen triggered reactions,unless a blocked form of the reactive compound is used, manufacturingmay need to take place in an oxygen free environment, such as a nitrogenatmosphere.

Specific exemplary blocked dyes and methods of preparing leuco-dyeprecursors are disclosed. Adhesive compositions which permit thede-blocking and oxidation of the leuco dye precursors at acceptablerates and methods of applying dyes and dye precursors to optical discsboth on the surface of optical discs and as bonding layers for opticaldiscs are disclosed (see previous patents for methods).

Also disclosed is the use of basic materials to increase the rate ofde-blocking of the protected leuco dye precursors in blocked leucodye-containing layers in or on optical discs.

Classes of dyes available for use in Blu-ray include for example, butare not limited to, azomethine dyes, acridines, styryl type dyes,cyanine dyes, oxonols, merocyanines, anthraquinones, naphthoquinones,quinoneimines, diaryl and triarylmethane type dyes, phenazine dyes,thiazine dyes, oxazine dyes, coumarin type dyes, and polyhydroxybenzenesor aminophenol derivatives. Preferred classes of these dyes are shownbelow. These structures are not intended to be all inclusive but toserve as examples of useful dye classes. Members belonging to thesedye-classes are reduced easily, can be air oxidized, and either absorbin the desired spectral window of 400-450 nm for blocking the readinglaser or slightly further to the red. The fact that their maximumabsorption peak is not exactly in the effective window is not a problemas long as their absorption curves are broad and increasedconcentrations lead to the desired coverage in the window.

As an example, the following synthetic scheme starting with the wellknown phenothiazinone dye, methylene violet, leads to a reduced andblocked compound that after de-blocking leads to air oxidation andregeneration of the starting dye. This process is similar to thatdescribed in U.S. patent application Ser. Nos. 10/163,473, 10/163,855,10/163,472, 10/837,826, 10/163,821, 10/651,627 and U.S. Pat. No.6,756,103, all hereafter incorporated by reference in their entirety,which describes the process for using methylene blue in 650 nm DVDapplications. The methylene violet dye has a broad absorption peak at580 nm with a strong secondary peak at 470 nm. At reasonableconcentrations, it can provide good absorption in the 400-450 nm window.

The compound has the added benefit that two blocked colorless forms ofthe dye can be made which are stable to air oxidation, but followingde-blocking yield the leuco-form of the dye which rapidly air oxidizesto the colored form.

As stated above, other potential chromophores for use are thequinoneimines, including indamines, indophenols, and indoanilines, suchas those disclosed in U.S. Pat. No. 5,424,475, herein incorporated byreference in its entirety.

Specific Examples

The quinoneimines along with the naphthoquinone and anthraquinone dyesare further described in the literature at M. Matsuoka, et al., J. Soc.Dyers Colour, vol 103, p 167 (1987) and “Chemistry and Applications ofLeuco Dyes”, chapter 2, edited by Ramaiah Muthyala, Plenum Press, NY(1997)

Specific Examples

Diarylmethane and triarylmethane dye types, such as those disclosed inU.S. Pat. No. 5,330,864 and herein incorporated by reference in itsentirety, are also potentially useful for this application and includefor example:

Although it usually requires a strong oxidant to oxidize the reducedform of this type of dye, there are some that can be air oxidized in thepresence of catalyst and light.

Further information can be found in the literature such as:Chemistry andApplications of Leuco Dyes”, chapter 5, edited by Ramaiah Muthyala,Plenum Press, NY (1997)

Oxazine, thiazine, and phenazine dye types are also appropriate for theapplication in blue laser optical disc formats. Leuco forms of all thesetype dyes are known. Phenazines may be especially useful since theygenerally absorb close to the desired region. Derivatives of thiazineand oxazine dyes are known that are close enough to the desired regionso that high concentrations give coverage.General Structure of These Dyes:

Where R1, R2, R3 is NZ₂, NHZ, hydrogen, alkyl, aryl, alkoxy, halogens,hydroxyl, CN, substituted thiols, SO2 alkyl, SO2 aryl, CO2 alkyl, or CO2aryl, where alkyl and aryl can be substituted and may include atomsnecessary to complete an aromatic or acyclic ring system, which maycontain heteroatoms and substitution, where Z can be selected from thegroup of hydrogen, alkyl, aryl, alkoxy, substituted alkyl, alkoxy, andaryl, substituted alkyl, alkoxy, and aryl, SO2 alkyl, SO2 aryl, CO2alkyl, or CO2 aryl, where alkyl and aryl can be substituted and mayinclude atoms necessary to complete an aromatic or acyclic ring system,which may contain heteroatoms and substitution.

-   -   Where X is selected from NZ, O, S, N, or Se.    -   Where Y is selected from O or NR.

Specific Example

Further descriptions of these dyes are included but not limited to“Chemistry and Applications of Leuco Dyes”, chapter 3, edited by RamaiahMuthyala, Plenum Press, NY (1997). References for thiazine, oxazine andphenazines can be found at J. Daneke et al., Ann Chem., vol 740, p 52(1970); B. I. Stepanov, Izv. Vyssh. Zaved. Khim. Khim. Tekhnol., vol 24,p 341 (1989); U.S. Pat. Nos. 4,622,395; 4,670,374, herein incorporatedby reference in their entirety; European patent 177,328; U.S. Pat. Nos.4,478,687; 4,647,525; 4,889,931; 4,889,932, all herein incorporated byreference in their entirety and European patent 339,869

While members of the above classes of dyes can be useful for providing areactive material to prevent a blue laser from reading encoded data inboth HD-DVD and Blu-ray optical media formats, it was found that the useof 2-arylamino-1,4-naphthoquinones were especially useful do to the easeand cost of their synthesis. 2-arylamino-1,4-naphthoquinones with thedonor groups confined to the quinoid ring form a class of compounds witha relatively low intensity visible band (ε˜4000) in the range of 430-500nm for a single amino-donor or near 550 nm if two amino groups arepresent. Substituents in the aryl ring have the effect for a typicaldonor-acceptor chromogen, and the absorption maxima fall in the range of435-560 nm for electron withdrawing vs donating substituentsrespectively. The isomeric 4-arylamino-1,2-naphthoquinones may also beused and affords the advantage of greater absorption intensities(ε=10,000). In the case where oxygen (air) is the stimulus for causingthe optical media to become unplayable, the reactive colorlessleuco-form of these compounds are useful but must be protected frompremature air oxidation during the manufacturing process. This can beaccomplished by a variety of blocking groups including but not limitedto esters, silyl ethers, carbonates, phosphinates, sulfonates, andethers (see US 2004/0137188 A1 for other leaving groups). The type ofblocking group can be chosen to give a specific rate of hydrolysis(de-blocking) in order to give control of the manufacturing process.Examples of synthesized dyes are given in FIGS. 1-3. The de-blocking ofthe protective group is accomplished with the aid of a variety of basicprimary, secondary and tertiary amines including but not limited toimidazole, diisopropylamine, dodecylamine, tripentylamine, tinuvin 292,aminohexanol, aminoethylmorpholine, dihexylamine, diisobutylamine,aminoethylpiperazine, aminoethoxyethanol and dioctylamine. As would beexpected, the hydrophilic/hydrophobic character of the adhesive can havea pronounced effect on both the rates of de-blocking and air oxidationof the leuco-form of the dye. Generally, the rates are faster inhydrophilic environments.

In order to evaluate the various novel blocked dyes as well as otherparameters involved in their ultimate use, discs were initially preparedthat did not contain the reflective layer in order to follow thekinetics of de-blocking and air oxidation using a UV/visiblespectrometer (Varian Cary 50 Scan). The general synthetic scheme,(examples 1, 2) used to prepare the various derivatives of2-(N-methylaminobenzene)-1-4-napthoquinone is given below. This samescheme was used to prepare the unmethylated derivatives by using anilineas the starting material. FIG. 4 represents data from a disc made asdirected and then observed in air over a 70 hr period. Initially, thereis no absorption in the visible region of the spectrum but after the 70hr period complete oxidation of the de-blocked, leuco-dye has occurredas evidenced by the peak at 463 nm (the absorption peak of2-(N-methylaminobenzene)-1-4-napthoquinone). Similar discs which werevacuum sealed in cryovac bags with oxygen scavengers remained colorlessduring this same time period both at room temperature and at 60° C.indicating that the transformation from a colorless to a colored stateis oxygen driven. FIG. 5 indicates that the rate of de-blocking of theprotected dyes is dependent on the base used. Thus by regulating theamine used it is possible to design the time frame for the de-blockingreaction. Likewise, if one keeps the base a constant in the adhesive mixand varies the protected dyes used, one observes various rates ofoxidation (de-blocking) depending on the dye and protective group (seeFIG. 60). Therefore by regulating both the base used and the blockinggroup used to protect the dye it is possible to provide limited playdiscs with designed time limits of play.

Example I Preparation of 2-(N-methylaminobenzene)-1,4-naphthoguinone

To a 250 ml round-bottomed flask is added 5.00 g (0.032 moles) of1,4-naphthoquinone (Aldrich Chemicals, Milwaukee, Wis.), and 90 ml of200 proof, anhydrous ethanol. This mixture is heated to reflux untilcomplete solution occurs at which point the temperature is lowered to50° C. This solution is stirred using a magnetic stirrer and 4.06 g(0.038 moles) of N-Methylaniline (Aldrich Chemicals, Milwaukee, Wis.) isadded. This is stirred for 3 hrs at 50° C. and then the temperature islowered to 40° C. for several hours and allowed to cool to roomtemperature overnight. A precipitate forms. The mixture is reheated to40° C. for 2 more hours and allowed to cool to room temperature beforefiltering off 1.0 g of tan solid using a Buchner funnel and #4 filterpaper. The filtrate is allowed to stir another 12 hrs at roomtemperature and then filtered to yield 2.45 g of orange crystals. Thefiltrate is concentrated down using a rotary evaporator to ˜30 ml andlet stand overnight. An additional 1.65 g of product is isolated for atotal of 4.15 g (50% total yield). The dye can be recrystallized frommethanol or ethanol and has an absorption max. in MeOH of 463 nm.

Example 2 Preparation of Chloroacetylated Dye 4-60

To a 100 ml addition funnel is added 50 ml of methylene chloride, 0.50 g(0.002 moles) of 2-(N-methylaminobenzene)l, 4-naphthoquinone, 50 ml ofwater, 0.30 g (0.001 moles) of tetrabutylammonium bromide (TBABr) and0.75 g (0.004 moles) of sodium hydrosulfite (Aldrich Chemicals,Milwaukee, Wis.). This mixture is gently shaken until the methylenechloride layer changes color from orange to light yellow (the reducednaphthoquinone). The addition funnel is then placed on top of a mediumfritted funnel containing 5 g of sodium sulfate drying agent that isattached to a 100 ml three-necked round-bottom flask containing 30 ml ofmethylene chloride kept at 5° C. using an ice bath. The entire system ispurged with argon while the methylene chloride layer containingleuco-dye is passed from the addition funnel through the sodium sulfatepad into the cold flask. To this cooled solution is added 0.6 ml (0.004moles) of triethylamine followed by 0.32 ml (0.004 moles) ofchloroacetic acid (Aldrich Chemicals, Milwaukee, Wis.). This solution isstirred at 10° C. for 2 hrs and then allowed to warm to room temperatureover the next 4 hours. The solution is then evaporated down to neardryness using a rotary evaporator. To this dark residue is added 50 mlof ether causing the formation of a white precipitate(triethyamine-hydrochloride). This is left overnight then filtered. Theether solution is evaporated to dryness on a rotary evaporator and thenthe residue is dissolved in 20 ml of a 6:4 mixture of methylenechloride/hexanes. This is then added to a 20×250 mm medium pressurechromatography column packed with 5-20μ silica gel which had beenpre-wet with the same mixture of solvents. The material is then elutedwith 7:3 methylene chloride/hexanes. The fractions containing purecompound are combined and evaporated to yield an oil which crystallizeson standing. The reaction and chromatography are monitored by TLC usingsilica gel coated plates and eluting with 7:3 methylenechloride/hexanes. This gives a product spot with an Rf=0.7 that turnsorange when treated with 1 N sodium hydroxide. 6.1 g of product isolatedas above was dissolved in 50 ml of n-butanol at reflux and let coolslowly at room temperature to yield 4.9 g of white crystals (M.P.101-102° C.)

Example 3 Preparation of Discs Using Dye 4-60

The adhesive used in the manufacture of the discs was composed of:Components Wgt % Supplier CD9038 62.87 Sartomer, West Chester, PA SR4948.30 Sartomer, West Chester, PA SR440 8.30 Sartomer, West Chester, PALowinox AH25 0.21 Great Lakes Chemical, W. Lafayette, IN Irgacure 8190.83 Ciba Geigy, Tarrytown, NY 2-Mercaptobenzimidazole 2.49 AldrichChemicals, Milwaukee, WI

4.5 g of Dye 4-60 is added to 124.5 g of the above formulation in a darkglass bottle and briefly heated to 60° C. This is then placed in asonicator (Branson model 2200) in which the water level is above thelevel of the adhesive mix in the bottle and sonicated for 15 min.Complete solution of dye results. To this solution is added a mixture of6.0 g of Sn(II)ethylhexanoate (Aldrich Chemicals, Milwaukee, Wis.) in12.0 g of Tri(propylene)glycol (Aldrich Chemicals, Milwaukee, Wis.).This is sonicated for several minutes after hand shaking to blend.Finally, to this clear solution is added 3.0 g (2%) of powderedimidazole (Aldrich Chemicals, Milwaukee, Wis.) and the mix is sonicatedfor an additional 15 min.

A DVD clear half disc (an umetallized 0.6 mm thick and 120 mm diameterpolycarbonate disc) is centered on a laboratory spin coating turntable.0.60 ml of the above dye/adhesive mix is applied uniformly in a circularring by a syringe at about 20 mm from the center of the disc. The discto be bonded is then placed over the adhesive and the combination spunat roughly 60-200 rpm's until the adhesive covers the entire discuniformly. At this point, the disc containing the adhesive isphoto-cured with a Xenon Cool Cure XL-DVD flash lamp using a 2 secexposure (10 pulses) set at its maximum setting. The process will yielda clear, fully cured acrylate bonded disc. Some discs were vacuum packedin cryovac bags containing oxygen scavengers in order to evaluate theirstability in an inert system (no oxygen). Compound 1

R R₁ COC₆H₅ H, CH₃ COCCl₃ H, CH₃ COCH₃ H, CH₃ COCF₃ H, CH₃ COCH₂Cl H,CH₃ Dye 6-62, Dye 4-60 COCHCl₂ H COCH₂OC₆H₅ H, CH₃ Dye 4-67, Compound 2

R R₁ C(CH₃)₃ H C₆H₅ H CH₂CCl₃ H Compound 3

R R₁ (C₆H₅)₂C(CH₃)₃ H (CH₃)₃ H, CH₃ (C₃H₇)₃ H, CH₃Manufacturing

Limited play optical media production involves a number of manufacturingelements. Typical of these elements are (i) premastering and/orauthoring, which creates the data to be encoded on each replicatedoptical media and/or modifies and/or readies the data to be included oneach replicated optical media so that the data is ready for glassmastering; (ii) glass mastering, which allows stampers to be created sothat each replicated optical media can be moulded; (iii) replication,whereby individual optical media are moulded using stampers created inthe glass mastering stage and followed by metallising and/or bondingand/or lacquer coating, in this element is also the inclusion of theread inhibiting reactive agent and/or material; (iv) printing of labelson each optical media; (v) packaging of each optical media into suitablepackages; and (vi) quality assurance, which ensures the optical mediameets necessary specifications regarding quality and/or playabilityand/or process controls.

The aforementioned elements need not occur at a single facility or underthe control of single entity or single organization. Moreover,additional elements may be added to the process. Further, all theaforementioned elements are not necessary in order to have an operableoptical media. For example, but not by way of limitation, it is notnecessary that each optical media have a label printed on it. The aboveoutlined elements need not be carried out serially and can be carriedout in parallel.

Premastering.

Source data, the data to be encoded on the optical media, is used tocreate a disc image on a suitable tape or other format. The originalmaster of the source data is copied to a specially prepared master,which is used to produce a master disc prior to replication. Formatsinclude, for example, Digital Linear Tape (hereafter “DLT”), U-matictape, DVD-R, DVD-RAM/-RW, CD, CD-R, 8 mm Exabyte, and DAT.

DLT is generally used for transferring DVD data for glass mastering.

U-matic tape is used as a digital audio media for mastering.

CD and CD-R discs contain necessary TOC and can be used as the directinput for CD audio and CD-ROM mastering.

DVD-R discs may be used to transfer the finished data for glassmastering for DVD-5 discs or DVD-10. DVD-9s cannot be mastered fromDVD-R.

DVD-RAM and DVD-RW discs cannot be used as input media for mastering.However, data files can be copied from a DVD-RAM or DVD-RW andpremastered to DLT or DVD-R.

8 mm Exabyte tape is physically identical to 8 mm videotape and can beused for mastering directly. Typically used for audio applications.

DAT may be used to master directly from provided certain parameters areadhered to, such as, certain audio rates are adhered to.

Glass Mastering.

Glass mastering is the process of transferring the premastered data intoa stamper that is ready for replication. The glass master begins as aglass substrate. The surface of the substrate is cleaned and then coatedwith a uniform layer of photo-resist material. For example, in DVDapplications the photo-resist layer thickness is 120 microns.

The glass master with the photo-resist is placed on the turntable of alaser beam recorder, where a laser is used to expose the photo-resist.The laser is modulated to expose the photo-resist where pits should be,while the glass master spins at exactly the correct linear velocity andis moved gradually and smoothly to maintain the correct track pitch andlinear velocity.

After the laser recording the exposed photo-resist surface is developedto remove the photo-resist exposed by the laser, creating pits in thesurface. The pits extend right through the photo-resist to the glassunderneath. The glass itself is unaffected by the development processand acts merely as a carrier for the photo-resist. After the exposedphoto-resist is removed the entire surface is metallised by sputtering ametal layer over the surface. Examples of metal used to sputter coat thesurface include nickel and silver.

The metallized glass master is electroplated with a metal, typicallynickel or silver, in a clean room environment to create a fatherstamper. This stamper can be used as the stamper for pressing finisheddiscs; however, to protect the integrity of the data on the masteradditional steps are taken to create children stampers. The fatherstamper is used to create a mother stamper through the process ofelectroforming. Son stampers are created from the mother stamper, againthrough the process of electroforming. The son stampers are then used inthe moulding in the replication of optical media. However, it is notalways the case that son stampers will be used for replication and aswill be further described in the below section.

Replication.

The finished stamper is fitted to a moulding machine ready to startmoulding the optical media substrates. For example, one stamper isneeded for CDs and one or two for DVDs. Optical media are made by firstmoulding the substrate and then metallising and/or otherwise coating atleast one substrate surface with a reflective material. The metallisingand/or reflective coating step can then be followed with lacqueringand/or bonding.

Moisture is first removed from optical grade polycarbonate. The moisturefree polycarbonate is injection moulded in a high pressure mouldingmachine, also known as a press, using the son stamper mounted in themould fixed to the press. This mould is in two parts and provides acavity, which ensures that perfectly moulded discs are produced with thecorrect dimension every time. One half of the mould contains the stamper(to form the pits) while the other half contains the mirror block toensure a smooth surface.

The hydraulic press applies to a force to the two halves of the mould,which are closed. Molten polycarbonate is then injected into the cavityand held in place by the applied pressure while the disc cools andsolidifies. During cooling the center hole is punched. After cooling,the press opens and the pressed disc is transferred to a conveyor toallow the disc to cool before the next stage. In the case of CDs, onlyone pressing is needed. In the case of DVDs, two pressings are neededand each half disc is half as thick as the single pressing of a CD.

The polycarbonate discs after moulding are transparent (or transparentat least to the intended reading beam of optical reading device thediscs are intended for). In certain limited play optical mediaapplications at least one of the polycarbonate disc halves is colored.The colorization of at least one polycarbonate disc half preventsphotobleaching when the read inhibiting reactive agent and/or materialis a photochromic dye. Further, the color of at least one polycarbonatedisc half also can prevent a disc playing in a next generation opticalmedia reading device that operates at a different laser wavelength.However, the color of the at least one polycarbonate disc half isselected so that the wavelength of the intended reading beam will not beinterfered with so that the encoded information can be read until theread inhibiting agent and/or material is activated.

At least one polycarbonate disc half of the optical media is covered bya mirror surface to reflect laser light from a laser beam of an opticalmedia reading device. The mirror surface allows the pits and/or otherdata features to be read by the laser light of an optical media readingdevice. Examples of mirror surfaces include, but not by way oflimitation, aluminum and silver. For example, silver is coated on atleast one polycarbonate surface by sputtering.

For single substrate optical media a protective coating is provided toprotect the reflective layer from corrosive elements. For example, CDstypically use aluminum as the reflective layer. This layer in CDs isprotected by a lacquer, which is spread as a liquid evenly across thesurface of the disc by spin coating. The centrifugal force created byspinning the disc ensures that the lacquer covers the whole disc in aneven layer. It is important that the lacquer overlap the aluminum thussealing it from the elements. If left exposed the aluminum will start tooxidize within a few days. The lacquer is cured by ultra-violet light,which produces a hard protective surface. Similar methods can beemployed with Blu-Ray discs.

For dual substrate optical media the two substrates are bonded togetherthrough the use of adhesives or other bonding agents. A number ofbonding solutions are available and include, for example and not by wayof limitation, hot melt bonding, radical UV cured bonding which involvesa UV cured resin similar to normal lacquer, cationic UV bonding whichinvolves screen printing the resin over both substrates and curing eachwith UV light and then pushing the discs together.

In one embodiment of the present invention, and as further described inU.S. Patent Application Nos. 20030152019, 20030123379, 20030123302,20030213710, 20030129408, and 20030112737 and as hereinafterincorporated by reference in their entirety, the read inhibiting agentand/or material is a constituent of the bonding material that bonds thetwo polycarbonate halves together. In this embodiment, the bondingadhesive is composed of at least two components that are combined in apredefined manner and under specified conditions. The combinationactivates the components. To allow the combination of the at least twocomponents in-line and during replication an auto dispense system isutilized. The auto dispense system can be a combination of pumps orother shaft driven dispense system that mixes at least two components inpredefined amounts and dispenses the combined product through a staticmixing tube. For example, the dispense system can be composed of adispense pump for each component where each component dispense pumpcontrols the volume of each component dispensed to make the adhesive; ora dispense pump that dispenses each component using a single actuatorand according to volumetric methods. The auto dispense system also hasthe ability to purge the static mixing tube and associated lines so thatthe system remains clean and free from clogs or older material that maycontaminate the system.

Variations on the above described replication process exist depending onthe type of optical media to be replicated. For example, U.S. PatentApplication Nos. 20030152019, 20030123379, 20030123302, 20030213710,20030129408, and 20030112737, describes an inverted mastering processfor manufacturing limited play DVD-5. U.S. Patent Application Nos.20030152019, 20030123379, 20030123302, 20030213710, 20030129408, and20030112737 are hereinafter incorporated by reference in their entirety.By way of background, a DVD disc may contain either one or twoinformation layers for each substrate, resulting to different types ofdisc capacities, such as DVD-5 (single sided, single layer, 4.7 Gbytecapacity), DVD-9 (single sided, dual layer, 8.5 Gbyte capacity), DVD-10(double sided, single layer, 9.4 Gbyte capacity), DVD-14 (double sided,one side single layer, one side dual layer, 13.2 Gbyte capacity), andDVD-18 (double sided, dual layer, 17 Gbyte capacity).

In one embodiment of the invention, the above process is modified byusing the mother stamper to replicate the L1 disc substrate half of aDVD disc.

In a long playing standard DVD-5 information is encoded on the L0 side(the substrate side closest to the reading beam of the optical readingdevice) with “pits” and “lands” molded on the L0 substrate andmetallized with a reflective coating. In this embodiment of the currentinvention, the mother stamper is used to mold the L1 side. This side issubsequently metallized and bonded with a blank (i.e., no data encodedsubstrate) L0 substrate. This results in the bonding layer in theoptical path. Using the specified layer thickness of 0.055 mm±0.015, thethickness of the L0 substrate is targeted at 0.55 mm to 0.57 mm duringmolding, to yield a focal length of the disc thickness (including thebonding layer) consistent with standard DVD specifications, allowing theplayer to be in the normal focusing range for reading a L0 layer. Thusthe player interprets the disc as a standard single layer DVD-5. Fieldexperience has shown that spacer layer thickness can be maintained at0.045 about 0.065 mm consistently in production. This controlledvariation in production along with the reduced thickness of the moldeddisc keeps the focus and optics within the specifications set by the DVDlicensing authority and the hardware manufacturers.

Labeling.

Optical media printing and finishing options vary, but all optical mediacan be printed on using similar technology. It is also possible to addserialization or other information to the optical media at this time.

The upper surface of a finished optical media can be printed with up tosix colors by a flat silkscreen process or offset printer. Each colorrequires a different screen created from label films produced as colorseparations from the artwork. The inks can then be cured using UV lightto produce a durable surface.

Serialization.

The burst cutting area is an annular area within the disc hub where abar code or other identifying information or serialization can bewritten. The BCA can be written during mastering and will be common forall discs from that master or, more usually, will be written using a YAGlaser to cut the barcode into the reflective layer of the finished disc.

In one embodiment of the present invention, serialization is an integralpart in ensuring the quality of the limited play optical mediamanufactured. For example, input values for each raw material used for aproduction run are input into a data storage system. These input valueswill then be linked to a unique bar code and/or serial number that willbe printed on the optical media. If a problem exists with the opticalmedia the optical media can be traced back to its input values and runconditions to determine the source of problem. In this embodiment inputvalues include, but are not limited to, information on (i) polycarbonatethat is used to create the substrate including born on date,manufacturer lot number, standard material properties, materialidentification, and oxygen diffusion rates, room temperature andhumidity storage, bar code information; (ii) packaging web material usedto package the optical media and allow for a predefined shelf lifeincluding born on date, manufacturer lot number, materialidentification, certificate of conformance, storage and shippingconditions since manufacturing, room temperature and humidity storageconditions and bar code information; (iii) adhesive part A including barcode information, born on date, manufacture lot number, materialidentification, certificate of conformance, storage and shippingconditions since manufacturing, room temperature and humidity storageconditions and bar code information; information on visual inspection ofcontainer seals; (iv) adhesive part B including bar code information,born on date, manufacture lot number, material identification,certificate of conformance, storage and shipping conditions sincemanufacturing, room temperature and humidity storage conditions, and barcode information, information on visual inspection of container sealsand ampule color, ampule spectral reference, measurement of absorbancespectrum, low temperature storage, dark storage conditions; (v) adhesivepart C information including bar code label information, born on date,material identification, manufacture lot number, certificate ofconformance, raw material references, visual inspection of containerseals, room temperature and humidity storage conditions; (vi) purgematerial information including bar code information, born on date,certificate of conformance; (vii) reflective sputter target materialinformation including bar code information, certificate of conformance,

In addition, information relating to the internal tracking of the inputmaterials once on site is cataloged. This information includes, forexample and not by way of limitation, (i) polycarbonate material isscanned prior to loading dryer; (ii) packaging material is scanned andcataloged before loading onto packaging machine, room temperature andstorage conditions are recorded; (iii) the adhesive is inspected andscanned before longing in auto dispense system and thus the replicationmachine information collected includes identification of part A andvalidation of shelf life, identification of part B and validation ofshelf life including quality control absorbance spectrum taken apredetermined time prior to loading on replication machine, internalmixing system absorbance measurement, identification of part C andvalidation of shelf life, identification of purge material andvalidation of shelf life; (iv) reflective sputter target material isidentified and validated prior to loading on replication machine.

Under this embodiment of the present invention, each replicated opticalmedia is serialized with a unique identification number prior to in-linefinished optical media scanning. The serialization forms an identifierto which the above inputs are traceable and for which the followingmanufacturing process variables are identified with the produced opticalmedia. These manufacturing process variables include, for example, (i)molding information, which includes lot indicator of polycarbonatesource, actual process values, process set points, and substratecorrelation reference information; (ii) replication information, whichincludes lot indicators for adhesive part A, part B, and part C, purgematerial, and sputter target material, process information such asactual process values (i.e., TCS and conveyor temperatures), process setpoints, finished optical media correlation reference; (iii) opticalmedia inspection parameters and test results, such as, standard DVD-5inspection parameters, optical layer thickness, reduced deviation, flowlines, particulates, manufacturing date and time stamp; (iv) packaginginformation, including lot indicators for both top and bottom webmaterials, process information from packaging machine, including dateand time stamp, actual process values (i.e., forming temperature andsealing times); process set points and UV irradiator status.

Packaging.

Optical media can be machine packed in a number of different packages.Some examples include: jewel case, slimline case, amaray case, superjewel box plus, super jewel box king, card wallets, and card sleeves.Packaging may also include sealed materials enclosing the disc andenabling a controlled environment as described in U.S. PatentApplication, Publication No. 2003/0213710, hereafter incorporated byreference in its entirety. The process parameters under which a limitedplay optical disc is package can influence the overall performance ofthe limited play optical disc. Process parameters, such as for exampleresidual oxygen content, activation levels of scavenging materialsincluded in the package, are recorded and stored to control batchquality. This information is part of the raw material input that islogged and linked to the disc through serialization.

Quality Assurance.

Quality assurance ensures that the optical media manufactured meetsmanufacturing specifications and allows monitoring of the processesinvolved in the manufacture of optical media and as such relates to allthe above outlined elements. Quality assurance is done at the masteringstage to ensure that stampers with good pit geometry are created.Typical stampers are played on a disc stamper player. The first disc tobe pressed is verified against the source to ensure that it has beenmastered without errors. The pit geometry of the glass master can beinspected using a suitable high power microscope.

Optical media are inspected and tested against a set of predefinedcriteria. For example, DVD optical media inspection and measurementsinclude measurement of tilt and bonding layer thickness. Testmeasurements include, for example, reflectivity, asymmetry checks, I3signal readings, I14 signal readings, push pull readings, cross talkreadings, jitter measurements, birefringence measurements, radial noisemeasurements, eccentricity, track pitch, scan velocity, begin of lead-in(hereafter “BLI”) measurements, begin of program area (hereafter “BPL”),begin of lead-out (hereafter “BLO”) measurements, radial and tangentialtilt tolerances are recorded.

The above measured parameters can change with time and environmentalconditions. Thus, part of the quality assurance includes measurementsover time and across different testing environments. Such test involve,for example, placing sample discs in an oven at a specified temperatureand humidity for a predefined period of time and then testing andmeasuring the sample discs again.

The foregoing disclosure is not limited the particular embodimentsdisclosed. The methods and system outlined above are not limited orrequired to be preformed in order and can be preformed in paralleland/or in a different order than that disclosed. The present inventionrelates to any method of tracking process and material inputs andlinking those inputs to a manufactured limited play optical medium.

Accordingly, the present invention has been described at some degree ofparticularity directed to the exemplary embodiments of the presentinvention. It should be appreciated, though, that the present inventionis defined by the following claims constructed in light of the prior artso that modifications or changes may be made to the exemplaryembodiments of the present invention without departing from theinventive concepts contained herein.

1. An optical medium readable by at least one pre-selected optical beamcomprising: a first substrate; a first data storage layer proximate tosaid first substrate, wherein said first data storage layer comprises anencoded information receiving layer and a reflective layer; and a readinhibiting agent, said read inhibiting agent in communication with saidfirst data storage layer, wherein said read inhibiting agent allowsaccess to at least a portion of said first data storage layer for apredefined period of time and after such predefined period of time saidread inhibiting agent irreversibly prohibits access to said at least aportion of said first data storage layer; wherein said read inhibitingagent absorbs optical radiation of said at least one pre-selectedoptical beam in the range of 350 nm to 450 nm, thereby prohibitingaccess to said at least a portion of said first data storage layer. 2.The optical medium according to claim 1, wherein said first data storagelayer is a Blu-Ray data storage layer.
 3. The optical medium accordingto claim 2, wherein said read inhibiting agent transforms from asubstantially transparent state to a state that interferes with thepassage of light in response to predefined stimulus, said readinhibiting agent comprising: a reactive material, wherein said reactivematerial has a first state that is substantially unreactive with saidpredefined stimulus and a second state that is substantially reactivewith said predefined stimulus; wherein said first state comprises atleast one blocked dye derived by the reduction of a dye selected from atleast one of azomethine dyes, acridines, styryl type dyes, cyanine dyes,oxonols, merocyanines, anthraquinones, naphthoquinones, quinoneimines,diaryl and triarylmethane type dyes, phenazine dyes, thiazine dyes,oxazine dyes, coumarin type dyes, and polyhydroxybenzenes or aminophenolderivatives and combinations thereof; and said second state comprises atleast one blocked dye un-blocked; wherein said at least one blocked dyederived by the reduction of a dye having the formula (1):

wherein R₁-R₄, R₇ each independently is selected from hydrogen, alkyl,aryl, alkoxy, halogens, hydroxyl, CN, substituted thiols, SO₂ alkyl, SO₂aryl, CO₂ alkyl, or CO₂ aryl, where alkyl and aryl can be substitutedand may include atoms necessary to complete an aromatic or acyclic ringsystem, which may contain heteroatoms and substitution; R₅, R₆ eachindependently is selected from hydrogen, alkyl, aryl, alkoxy, wherealkyl and aryl can be substituted and may include atoms necessary tocomplete an aromatic or acyclic ring system.
 4. The optical mediumaccording to claim 3, further comprising a reducing agent.
 5. Theoptical medium according to claim 4, wherein said reducing agent isstannous ethylhexanoate.
 6. The optical medium according to claim 4,wherein said reducing agent is selected from at least one of solubleSn(II) compounds, soluble iron (II) compounds, reducing saccharides,ascorbic acid and its derivatives hydroxylamines, hydrazines,dithionites with a solubilizing counter ion, alpha-hydroxyketones,appropriately substituted boron and silicon hydrides, and combinationsthereof.
 7. The optical medium according to claim 3, further comprisingat least one basic substance.
 8. The optical medium according to claim6, wherein said at least one basic substance is selected based on theability to act as an unblocking catalyst.
 9. The optical mediumaccording to claim 6, wherein said at least one basic substance isselected from an organic amine group.
 10. The optical medium accordingto claim 9, wherein said at least one basic substance is selected fromat least one of imidazole, diisopropylamine, dodecylamine,tripentylamine, tinuvin 292, aminohexanol, 4-(2-aminoethyl)-morpholine,dihexylamine, diisobutylamine, 1-(2-aminoethyl)-piperazine,aminoethoxyethanol, dioctylamine, and combinations thereof.
 11. Theoptical medium according to claim 3, wherein the blocked dye has atleast one blocking group per molecule with said at least one blockinggroup on the phenolic oxygens.
 12. The optical medium according to claim3, wherein the blocked dye has two blocking groups per molecule with theblocking groups on the phenolic oxygens.
 13. The optical mediumaccording to claim 11, wherein said at least one blocked dye is from thereduction of 2-arylamino-1,4-naphthoquinone type dyes;
 14. The opticalmedium according to claim 13, wherein said at least one blocked dye isderived from the reduction of2-(N-methylaminobenzene)-1,4-naphthoquinone.